Crab Population Decline Since the Late Pleistocene

Predation Scars Reveal Declines in Crab Populations Since the Pleistocene

Kristina M. Barclay, Lindsey R. Leighton

Summarized by Nicholas Stanton, a geology major at the University of South Florida. Nicholas is a Navy veteran who went back to school to follow his passion in the study of Earth’s history. Nicholas has worked for USGS for 2 years as a hydrographer, continuing his love for all things science.

Data that were used: The number of customers that visited Joe’s Crab Shack in a month was the determining…. JOKING. The data that was used in determining if there was a decline in crab populations is quite fascinating and it starts with snails. The Tegula funebralis to be specific, but to make it a little easier these can be referred to as a black turban snail. These snails are extremely helpful, telling stories of the past by their healing attributes. They leave remarkable healing scars after attacks from predators, also known as predation scars.

Methods that were used: So, we just count how many snails have predation scars and that accounts for how many crabs there are in the ocean right? Well, there are a few other factors that need to be eliminated before we can equate these two pieces of information. For example, can the failure of crab attacks account for fewer scars due to the snail shell never being penetrated to create a scar in the first place? Or, can the size of the snail and the size of the crab determine the amount of predation scars found? Well, it is a good thing science rules and we have a bunch of cool scientists that have already conducted studies to help in answering these questions. Other studies have inadvertently shed light on this by answering these questions, even though the purpose of their study was not to calculate crab populations. This other study ended up showing that a change in the success of crab predation is not an explanation for a change in repair frequency. Instead, it is likely that the change in repairs is caused by the change in crab population. In the study summarized here, fossil and modern specimens were collected to compare and determine the crab abundance dating back from the Pleistocene to present day, with the maximum geologic age for the fossils extending to 120 ka (thousand years). Most of the fossils were taken in southern California, specifically the Palo Verdes Hills and the San Diego area. The modern specimens also came from these same areas as to reduce biases in the study. A total of 712 fossil specimens were gathered, 261 from the Palos Verdes Hills area and 451 from the San Diego area. The modern specimens came from seven locations in the same two areas previously listed. Collecting these modern samples was tedious to ensure certain biases did not enter the study. Researchers would walk up and down in symmetrical lines spaced two meters apart collecting around ten to twenty snails on each line. This was done until a total of 1,152 snails total were collected.

A dark colored snail with a cone shape that gets narrower as it extends upward. There is scar, which is a jagged vertical scar that covers 2/3rds of the cone shaped shell on the side. This scar was caused by predation from a crab. Left is a side view, right is a bottom view of the snail
Figure 1: These are examples of predation scars on the black turban snail. In box A the red arrow is pointing to a typical repair scar seen in these snails. Box B shows the size of the snail being taken at the time of attack. This helps show the size at which the snail was and the success of the attack. A snail with a high conical shape and a large groove covering nearly 2/3 of its body shows signs of repair from predation scars.

Results: It was discovered that modern black turban snails have fewer scars than those fossils dating back to the Pleistocene. It was concluded from the study that changes in the frequency of repairs since the Pleistocene is indicative of a change in the number of attacks. The maximum size of repairs between the fossils collected and modern samples were similar, showing crab strength had not changed much over the years. This helped eliminate the thought that lower predation scars were due to the lower success of attacks. This tells the researchers that the crab population has declined since the Late Pleistocene, due to the decline in predation scars in snails.

Why is this study important? Paleontology is crucial for understanding the story book of Earth’s past. It is a nice guide in determining questions about Earth’s future, as well. Fisheries have poor data and little money to invest in expensive research on how to maintain their fishing numbers in the ever-declining industry. Overfishing is playing a huge part in the decline of not only crab population, but thousands of species of marine life. For example, Somalia was once a successful fishing port, but due to larger countries overfishing those waters, the economy collapsed. This is a devastating notion that an entire country’s economy can be significantly affected due to overfishing.

The big picture: This study has mapped an entire population of crab, and this can inform fisheries on how to sustain a healthy number, without depleting the entire species. Things such as climate change, long line fishing, and pollution are wiping out our marine diversity swiftly. Paleontologists, as well as all other scientists, understand the effects of climate change and pollution on Earth’s ecosystem. These scientists are on the front lines combating these realities with knowledge, with evidence, and with SNAILS! 

Citation: Barclay, K. M. & Leighton, L. R. (2022). Predation scars reveal declines in crab populations since the Pleistocene. Frontiers in Ecology and Evolution. https://www.frontiersin.org/articles/10.3389/fevo.2022.810069/full 

The Youngest Pangolin Species Originating From Europe Has Been Found in Romania

The youngest pangolin (Mammalia, Pholidota) from Europe

Claire E. Terhune, Timothy Gaudin, Sabrina Curran, Alexandru Petculescu

Summarized by Isabelle Snowball, a fourth-year geology student at the University of South Florida. She has a particular interest in GIS. In her free time, she enjoys various forms of art and spending time with her friends.

Key Terms: Pangolin – an armadillo-like mammal with scales covering its body, a long snout, long tapered tail, and long tongue which it uses to catch and eat insects; humerus – the bone in the upper arm of an organism; synapomorphy – a characteristic shared exclusively by a species and its descendants.

What data were used: Scientists in Graunceau, Romania uncovered a pangolin humerus–the youngest ever found in Europe. Specimens from this fossil collection are estimated to be from the Villafranchian age, a period of time ranging from the Late Pliocene to Early Pleistocene in an area scientists think represented a woodland environment. This dates the specimen to be around 1.8-2.2 million years old (Ma). The specimen is stored at the ISER (Institute of Speleology, Bucharest, Romania). Data from currently surviving species of pangolin were used to compare other humeri measurements to those of the Smutsia olteniensis humerus, the fossil central to this study.

Methods: The pangolin humerus (Fig. 1) was appropriately photographed and cataloged, which included creating a 3-D model by scanning the specimen with an HDI 120 Blue Light scanner. The humerus was compared to data collected from the humeri of twelve other pangolin specimens—specifically examining measurements for length and width of a number of  shoulder, arm, and leg bones. 

Figure 1: A 3-D Model of Smutsia olteniensis humerus

Results: Scientists determined that the newly found specimen had all of the features of a modern pangolin, or Pholidota. Specifically, this specimen is more closely related to modern species of pangolin. Still, it boasted enough unique traits to earn its place as a new species of pangolin, Smutsia olteniensis. Given the woodland environment of the Graunceau site, we know it is possible that Smutsia olteniensis was open-adapted, meaning it preferred open woodlands as opposed to the tropical environments modern pangolins prefer.

Why is this study important? Little is known about the fossil record of the pangolin. They are believed to have emerged in Europe during the Eocene and disappeared from the European geologic record during the Miocene, potentially in search of warmer, more tropical environments. Up until now, the only evidence of pangolins’ existence during the Plio-Pleistocene came from Africa.

The big picture: With this newfound specimen dating back to the early Pleistocene, it appears that not only did pangolins stick around Europe longer than previously thought, but that they may have occupied a wider geographic range as well. Scientists have concluded two possibilities—the first being that pangolins may have remained in Europe as late as the Pleistocene, and the second being that they did migrate to Africa, but eventually made their way back to Europe by the Pleistocene. 

CitationsClaire E. Terhune, Timothy Gaudin, Sabrina Curran & Alexandru Petculescu (2021) The youngest pangolin (Mammalia, Pholidota) from Europe, Journal of Vertebrate Paleontology, DOI: 10.1080/02724634.2021.1990075

Lorenzo Rook, Bienvenido Martínez-Navarro, Villafranchian: The long story of a Plio-Pleistocene European large mammal biochronologic unit, Quaternary International, Volume 219, Issues 1–2, 2010, Pages 134-144, ISSN 1040-6182, https://doi.org/10.1016/j.quaint.2010.01.007. (https://www.sciencedirect.com/science/article/pii/S1040618210000170)

Northern Florida bear fossils reveals new species of Indarctos in North America

Coexistence of Indarctos and Amphimachairodus (Carnivora) in the Late Early Hemphillian of Florida, North America

Qigao Jiangzuo · Richard C. Hulbert Jr.

Summarized by Eric Kastelic, who is a geology major at The University of South Florida. Currently, he is a senior. Starting in Fall 2022, he will be pursuing graduate studies in hydrogeology focusing on groundwater recharge and once he earns his degree, he plans to work as a research hydrologist or become a research professor. When he’s not studying geology, he loves to go on walks with his friends and explore nature!

What data were used? ~ 7.5–6.5 million year old Indarctos fossils from the Withlacoochee River 4A Formation in Northern Florida, USA. These fossils were compared to previously collected specimens from elsewhere in the United States and China. 

Methods: This work descriptively compared ~ 7.5–6.5 million year old  Indarctos fossils form Northern Florida with corresponding Indarctos fossils from formations in Kansas, Texas, Oregon, California and Nevada. Additionally, fossils from Northern China were reviewed to connect a possible ancestral relationship.  

Results: This study investigated at least four Indarctos individuals found in the Withlacoochee River 4A Formation of Florida. As it is uncommon to find numerous individuals in one site, this fossil find marks one of the most comprehensive groupings of Indarctos fossils in in North America. These four individuals made it possible for the researchers to compare jaw, dental, neck, pelvic, and heel properties between the specimens at the formation and other Indarctos fossils worldwide. The similarities in dental characteristics between Indarctos of the Withlacoochee River 4A formation and I. oregonensis, a species of Indoarctos, paired with differences in slenderness of postcranial bones between the Florida specimens and I. oregonensis (skeleton excluding the skull) shows a at least two variations of postcranial bones in North America. What does this mean about the Florida Indoarctos? Is it a new species? This works makes no definite support or rejection of the Indarctos of the Withlacoochee River 4A Formation being a previously unknown species, but acknowledges the need for further research to determine this. 

 Photo of bear skull fossil from two differing areas with similar shape and size. The Indarctos skull fossils from the Withlacoochee River 4A in northern Florida is approximately 30 cm in length, yellow in color, has teeth with two prominent front teeth, and the piece of the skull between the top of the skull and nose is missing. The I. zdanskyi from Baode in North China is about 40 cm in length, white in color, has four prominent front teeth, and is missing the bone supporting the left side of the face.
Figure 1: Top, bottom, and side views of a Indarctos skull fossils from the Withlacoochee River 4A in northern Florida (A1-3) and a I. zdanskyi from Baode in north China (B1-3).

Why is this study important? This study shows a possible unique species of Indarctos that hasn’t previously been identified. Indarctos throughout North America show a differing type of bone robustness, despite not being geographically separated. This work documents that Indarctos may have ancestors in northern China, showing a possible movement to North America from Eurasia in the geologic past. This work, paired with fossils of other fauna (animals) and climatic data, may be able to show shifts in ecosystems as a driver in the migration of Indarctos.

The big picture: New fossil finds strengthen understandings of how organisms moved across the globe in geologic time. The information gained form comparing Indarctos fossils provides insight into how other mammals may have moved.

Citation: Jiangzuo, Qigao, and Richard C. Hulbert. “Coexistence of Indarctos and Amphimachairodus (Carnivora) in the Late Early Hemphillian of Florida, North America.” Journal of Mammalian Evolution 28.3 (2021): 707-728.

The relationship between arm shape and lifestyle of brittle stars

The evolutionary relationship between arm vertebrae shape and ecological lifestyle in brittle stars (Echinodermata: Ophiuroidea)

Mona Goharimanesh, Fereshteh Ghassemzadeh, Barbara De Kegel, Luc Van Hoorebeke, Sabine Stöhr, Omid Mirshamsi, and Dominique Adriaens

Summarized by Emma Nawrot, who is a geology major at The University of South Florida and is currently a senior. Once she graduates, she plans on pursuing a career in Volcanology and Igneous Petrology. In her free time, she enjoys playing video games, hiking, and going to the beach!

What data were used? This study examined species of Ophiuroidea (brittle stars) that were specifically chosen to cover a large range in both species type and lifestyles that corresponded to distinct functions of their arms. Samples were gathered from fossils of the Persian Gulf and Oman between December 2017 to March 2018 and were classified based on their lifestyle and joint type. 

Methods: This study used a 3D analysis of a range of brittle star species to determine the structural relationships of their arm vertebrae (here, meaning the distinct pieces of their arms). Species were carefully chosen to cover a range of operational lifestyles associated to different usage of their arms. This included prehensile (grasping) and non-prehensile (non-grasping) species. At minimum, one specimen per species was utilized, across to seven families throughout the broader groupins within the ophiuroids. To obtain a better resolution of the structures, portions were removed from the middle and outer part of one arm per sample of brittle star for CT scanning. Every sample was CT-scanned using a HECTOR scanner. The vertebrae were digitally segmented from the CT scans produced and 3D models were created using a software called Amira. The acquired 3D model of each arm skeletal piece was then transformed into data that the computer could use to determine the differences in shapes between each of them. 

On the left is a diagram of a phylogenetic tree that displays the twelve different species used in the study and their relationships to one another as they have evolved through time. To the right of this tree are the 3D shapes of their arm skeletal pieces and joint types shown from two different perspectives: distal is shown on the left and proximal is shown on the right. The names of the joints are listed in grey and yellow boxes to the right of the shapes, with the grey representing the distal viewpoint and the yellow representing the proximal. The different species on the phylogenetic tree are highlighted in pink, yellow, and green depending on their lifestyle. Epizoic or living on another animal, are highlighted in pink. Endozoic or living within another animal are highlighted in yellow and epiphytic or growing on the surface of a plant are in green.
Phylogenetic tree of the 12 species used in this study and corresponding arm shape and life habits.

Results: The study showed that there was a significant amount of variability found in the arm vertebrae of different species of brittle stars. The results reflect how these structural differences represent specific adaptations, such as having the ability to hold onto other objects and creatures. Furthermore, unique shapes of arm vertebrae in brittle stars were found to be directly correlated to their functional and environmental lifestyles. It was observed that some species that were not strongly related, still converged to a comparable design in arm shape. Perhaps the most remarkable results that came from the study were the patterns of how the shape of brittle star vertebrae is directly associated to unique evolutionary adaptations. For example, the species Ophiura sarsii has longer distal arm skeletal pieces than Ophiocamax vitrea, which is a non-prehensile organism, meaning it cannot grasp onto objects. Ophiura sarsii is known to take part in significantly more hunting behaviors than Ophiocamax vitrea, and these longer arm skeletal pieces create a greater yielded force. This is an indispensable factor for its hunting activities as an active predator. 

Why is this study important? This study sheds light on the intricate nature of shape deviations in brittle stars and how these changes relate to their distinctive adaptations. It is the first study to connect morphological attributes of brittle stars to their modes of life using 3D modeling of their vertebrae. Through this modeling, insight was gained on the unique functional and ecological lifestyles of different species of brittle stars. Without understanding this relationship, we can’t begin to understand how these organisms changed over time and the evolutionary patterns they show. 

The big picture: Ultimately, this study will be extremely helpful in the future for inferring information that we can apply to the fossil record. For example, paleontologists often find disarticulated bits of ophiuroids where it’s difficult to ascertain their origins and morphological traits, so this could be helpful for researchers in pinpointing these patterns when there’s not much other data to go on.

Citation: Goharimanesh, M., Ghassemzadeh, F., De Kegel, B., Van Hoorebeke, L., Stöhr, S., Mirshamsi, O., & Adriaens, D. (2021). The evolutionary relationship between arm vertebrae shape and ecological lifestyle in brittle stars (Echinodermata: Ophiuroidea). Journal of anatomy.

Understanding the Fossil Record of Tiger Sharks

Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time

Julia Türtscher, Faviel A. López-Romero, Patrick L. Jambura, René Kindlimann, David J. Ward, and Jürgen Kriwet

Summarized by Austin Crawford, a senior obtaining a Bachelor of Science in geology at the University of South Florida. Austin’s current career interests involve several fields in hydrology/hydrogeology, engineering geology, geologic/environmental consulting, geophysics, mine geology, oil and gas (OG), and geomatics. Aside from education, Austin enjoys spending time outdoors, riding his motorcycle, watching sports, listening to music, and spending time with family and friends. 

What data were used? 569 isolated teeth of both extinct and the extant (still living) tiger shark were examined for the basis of determining the geometric morphometrics, which is a method used to quantify shape of the teeth and disparity, which indicates differences between teeth of Galeocerdo. The ages of the teeth were also recorded. 

Methods: The 569 teeth samples (Figure 1) were each photographed with a labial aspect representation, which is the surface towards the lips. In addition, 18 published illustrations were included to compensate for more complete representation. The specimens were analyzed using a two-dimensional geometric morphometric system using landmarks. This means that the same 64 locations on each tooth were marked in a computer program (tpsDIG2). These landmarks were analyzed using a Generalized Procrustes analysis (GPA), which compared the differences in shapes across all of the teeth and summarized how different each of the shapes were. These data were analyzed using a Principal Components Analysis (PCA), which plots all of the variables’ differences into a 2D plane for easier analysis. Qualitative shape analysis by the researchers was also considered in the later portion of the study to describe features that weren’t included in the prior study, such as serrations in the teeth that are key identifiers for species within the genus Galeocerdo. 

Results: The conclusion of the procedure yielded three identified genera: Galeocerdo, Hemipristis, and Physogaleu and two unclear species, G. acutus and G. triqueter . The three genera and two species groupings were identified from the PCA, which showed the three distinct genera plotted on the graph. From the original 23 identified species of tiger shark, researchers here determined only 16 were legitimately considered because seven lacked illustrative characteristics. The distribution of these 16 species of Galeocerdo was made using the same processes used for the broader classification of all 569 shark teeth. The disparity through time for the tiger sharks falls into geologic time spans of Paleogene and Neogene-Quaternary. The PCA showed groupings of sharks by time spans, too. Paleogene sharks (G. clarkensis, G. eaglesomei, and G. latidens) occupy a distinct area of the principal components chart, indicating they are similar in shape. Tiger sharks within the Neogene-Quaternary are notably different in shape. 

The descriptions for all Galeocerdo species teeth are in lingual view (side of the tongue) with the distal side on the right and medial side on the left (away from the center of the mouth and toward it, respectively). Galeocerdo aduncus (A) is tan in color, smooth and is the smallest specimen of the six, coming close in size only to Galeocerdo clarkensis holotype (C). A contains rounded root lobes, strong serrations along distal side, strong notched distal edge, and very fine serrations along one side. Galeocerdo capellini (B) has a darker tan combined with some orangish and red tone, considerably rough texture, and is the largest of the six samples in size. Specimen B has the most rounded root lobes, conjoined rounded serrations, weakly notched distal edge, and medium sized with rounded serrations along the mesial side. Galeocerdo clarkensis holotype (C) is the roughest textured tooth of all six species, relatively small compared to the others, and has a combination of colors in green, grey, and brown. The morphology of C is the most abnormal compared to that of the remaining five shark tooth samples. The specimen has a poor notch at the root, rounded root lobes, a small number of wide serrations, strong distal edge, and curved side with poor serrations. Galeocerdo cuvier (D) is most noticeable by its cleft. The boundary marks the change between dark color and extremely smooth textured surface to a light, rough region of the root lobe. Galeocerdo cuvier (D) is large in size compared to the holotype of Galeocerdo clarkensis (C). Sample D has a square-like root lobe, fairly notched distal edge and prominent serrations on both sides. Galeocerdo eaglesomei (E) holotype is the easiest to recognize shark tooth of the six specimens. E is black in color, smooth texture, and medium sized. The resemblance of Galeocerdo eaglesomei (E) is close to that of the general shark tooth one might think of. It has three strong points in a triangle form with the two-edged root lobes and fine point in the apical region, no distal notch, and contains well-formed serrations along both the mesial and distal sides. Galeocerdo mayumbensis (F) is medium in size, contains some texture, and is mainly tan with some darker areas near the root lobe. Sample F is highly convex and has square root lobes, very weak distal notch, and rolled serrations along both sides.
Different morphology (like serrations, the sharp projections), color, texture, and size of the six significant tiger shark species teeth samples. Scale bars= 10 mm.
A: Galeocerdo aduncus. B: Galeocerdo capellini. C: Galeocerdo clarkensis holotype. D: Galeocerdo cuvier. E: Galeocerdo eaglesomei holotype.F: Galeocerdo mayumbensis

Why is this study important? Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time serves an important part within the paleontology of Galeocerdo as a whole. The simple acknowledgement is beneficial to the genus. The authors state that this shark has been neglected compared to the other apex shark genera. The article is important to both the diversity and disparity between those diverse species of Galeocerdo throughout the Cenozoic. In doing so, the paleobiology of Galeocerdo can help with knowing phenotypes (the physical expressions of the genetic makeup) of the extant tiger shark today as well as its trend in the future.

The big picture: Apex sharks such as Galeocerdo serve an important purpose in the Earth’s oceans as they maintain the population of other prey. This results in an ecosystem balance for the plenty of other organisms that they feed off. Evidence shows that oceanic sharks and rays have been in decline globally since 1970 meaning a deteriorating diversity of higher order ocean species. Consideration of scientific studies on shark evolution is a way we as humans can protect the future of shark ecology.  

Citation: Türtscher, J., F. A. López-Romero, P. L. Jambura, R. Kindlimann, D. J. Ward, and J. Kriwet. 2021. Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time. Paleobiology, 47:574–590.

The Scope of Agricultural Climate Change Mitigation Goes Beyond Production Stages

Climate change mitigation beyond agriculture: a review of food system opportunities and implications

Meredith T. Niles, Richie Ahuja, Todd Barker, Jimena Esquivel, Sophie Gutterman, Martin C. Heller, Nelson Mango, Diana Portner, Rex Raimond, Cristina Tirado, Sonja Vermeulen

Summarized by Taylor Dickson, who is a senior currently majoring in Environmental Science at Binghamton University. They are an environmentally conscious and dedicated student with a hunger for knowledge. Taylor plans on pursuing field experience prior to the continuation of their education. Outside of the realm of education, they enjoy immersing themselves in nature as well as participating in and appreciating the arts.

What data were used? The data utilized in this article are derived from other research articles and compounded to create a bigger picture encompassing all aspects of the food system. This article incorporates important information regarding areas beyond the direct scope of food production. Such areas included are transportation and refrigeration methods, which have greenhouse gas emission consequences.

Methods: Combining and integrating recent research and expanding the exploration of mitigation opportunities by reviewing the relevance and effectiveness of these opportunities in several areas throughout the food system including pre-production and post-production. This study goes below the surface issue to expose the root areas that need to be addressed to create a more sustainable food system.

Results: The results incorporate all aspects of the food system while considering agricultural climate change mitigation. Included in these results are aspects of food production many people may often forget about including the transportation and storage of the food produced. Certain foods have higher emissions associated with them due to the necessary storage required for these food products as well as the circumstances surrounding the growing and harvesting of such products.

Food loss is experienced at all levels of consumption within the food system, including the pre- and post-consumer levels. Annually, about one third of all food products produced on a global scale result in being wasted or lost throughout the production process. At the production level of the food system, a significant source of greenhouse gas emissions is related to the production of synthetic fertilizers used for agricultural practices. This information demonstrates how vast the scope is of the food system discussed.

Greenhouse gas emissions are significantly higher regarding diets rich in animal derived products. This article utilizes other works which provide information and insight that shifting toward a more plant based diet will be beneficial to the environment in lowering greenhouse gas emissions as well as leading to a decrease in human mortality rate accompanied with an increase in health benefits.

Circular diagram separated laterally with 10 driving forces above and 5 categories of production and consumption of the food system below. Within the diagram is an inner circle of outcomes.
This figure visually portrays the different social, economic, and physical forces (i.e. politics, demographics, and infrastructure) that affect the several varying areas of production within the food system. This system is one that ranges from pre-production and production to the disposal of waste and lost food. From Niles et al. (2018).

 

Generally, refrigeration is necessary for around half of all food produced. Lower income countries often lose crops at the production stage due to a lack of technologies related to refrigeration and drying methods. Inadequate drying technologies lead to the development of mold and eventual spoiling of food products such as grains. Almost one fifth of the energy utilized by the food system in the United States is from household refrigeration. Transportation related emissions can be reduced primarily by shifting to more efficient modes of transportation. With many food products requiring refrigeration throughout the transportation process, greenhouse gas emissions of refrigerated transportation can reach up to 140% when compared to the emissions associated with non-refrigerated transportation vehicles.

Why is this study important? This study brings together results from previous studies in a cohesive paper which encapsulates information from several areas within the food system. Incorporating the many aspects of the food system in this study provides the reader with a broader understanding of the depth of each component within the system. A single issue of agriculture is broken down into multiple specific and more manageable subcategories where mitigation strategies are indulged. This study goes a step further and provides possible outcomes to the proposed mitigations and discusses potential consequences of these mitigation strategies.

The bigger picture: Climate change is an inevitable universal issue that everyone will face at some point in their lives, and one that demands immediate attention and mitigation. This study exposes the underlying issues of the food system that are significant contributors to climate change. It draws attention to the root causes of greenhouse gas emissions within the food system. The food system is much more than agricultural production. It includes often overlooked aspects related to pre-production and post-production such as packaging, transportation, and storage of the food produced. Although these issues begin at the production level with corporations, consumers hold some power and have the ability to aid mitigation strategies in their success. Some opportunities for these consumers to participate in as described in this article are to adopt a more plant based diet, refraining from over consumption, and understanding that perfection is an illusion and food does not have to be pleasing to look at for it to be nutritious and serve its purpose.

Citation: Niles, M. T. et al. Climate change mitigation beyond agriculture: a review of food system opportunities and implications. Renewable Agriculture and Food Systems 33, 297–308 (2018).

How machine learning techniques can be used in the reduction and removal of greenhouse gases

Tackling Climate Change with Machine Learning 

David Rolnick, Priya L. Donti, Lynn H. Kaack, Kelly Kochanski, Alexandre Lacoste, Kris Sankaran, Andrew Slavin Ross, Nikola Milojevic-Dupont, Natasha Jaques, Anna Waldman-Brown, Alexandra Luccioni, Tegan Maharaj, Evan D. Sherwin, S. Karthik Mukkavilli, Konrad P. Kording, Carla Gomes, Andrew Y. Ng, Demis Hassabis, John C. Platt, Felix Creutzig, Jennifer Chayes, Yoshua Bengio

Summarized by Samir, a first year masters’ student at Binghamton University State University of New York majoring in geosciences. He has experiences in designing and delivering effective solutions using programming skills and knowledge in geosciences, physics, and mathematics. Also, he is planning to dive into machine learning since he believes it is one of the most effective methods to tackle global issues! By the way, he is a big fan of basketball.

What data were used? One of the many datasets used in the study is a large-scale climate dataset for detecting, localizing, and analyzing extreme weather occurrences in a semi-supervised manner. The discoveries, assumptions, significantly important results, and models present in this study wouldn’t be possible without historical climate dataset, high-resolution satellite images, video, CO2 emissions, remote sensing data.

Methods: The methods that were already used or might be potentially used in the future include but are not limited to remote sensing of emissions, precision agriculture, monitoring peatlands, managing forests, and carbon dioxide removal. It should be mentioned that there were more domains discussed in the original study, however this particular summary mainly focuses on implementation of machine learning on farms, forests, and carbon dioxide removal techniques to tackle climate change. Figure below provides the summary of methods and areas of implication mentioned above. The most impactful and interesting methods will be discussed in detail.

Figure 1. Selected strategies to mitigate greenhouse gases emissions from lands Simple sketch of areas of interests and selected machine learning techniques that can be potentially applied in the farmlands: precision agriculture (left side of the figure), peatlands: monitoring peatlands (middle side), and forests: estimating carbon stock, automating afforestation, managing forests fires (right side) while controlling emissions using remote sensing of emission (top side). Image from Rolnick et al., 2023.

 

It might sound as a surprise; however, agriculture is responsible for 14% of the greenhouse gas emissions. Modern methods used result in massive, sequestered carbon release, such as in particular: tilling, which basically exposes topsoil to the air which is the reason behind release of locked carbon that was bound to soil. Also, as some agricultural techniques deplete soil nutrients, nitrogen-based fertilizers must be reintroduced. However, while some nitrogen is up taken by plants, the rest is being transform to nitrous oxide – a greenhouse gas 300 times more powerful than CO2

Precision agriculture, which is the combination of tools and machine learning methods, can be used to make it possible for farmers to work on a large scale and not diminishing production as it happens when conventional methods are used. For instance, the hyperspectral camera-equipped robot can undertake mechanical weeding, targeted pesticide application, and insect vacuuming. Monitoring peatlands, one of the main sequestered carbon sources in the world, is essential. It is not only releasing carbon while decomposing but also is susceptible to fire. Therefore, identification and estimation of these carbon “stocks” through machine learning techniques plays an important role in potential fire risk assessment. 

One of the main points made in the study is even if all the emissions stop today, because of the carbon that is already in the atmosphere, the planet will still experience consequences of global warming. Direct CO2 capture and consequent sequestration is a most reliable and promising solution. The main concept underlying direct air capture (DAC) is to blast air over CO2 sorbents, and then employ heat-powered chemical processes to purify the CO2 for sequestration. To optimize sorbent reusability and CO2 absorption while reducing energy consumption, machine learning might be utilized to speed up materials discovery, process engineering operations, such as corrosion-resistant components. 

Consequent step is to sequestrate carbon dioxide. Direct injection into geologic formations such as saline aquifers, which are analogous to oil and gas reservoirs, is the best-understood method of CO2 sequestration. Machine learning can be utilized to find potential storage locations. Also, machine learning can contribute to the maintenance of active sequestration sites and monitor them in order to detect potential leaks CO2 leaks.

Results: As for the results of the study, such as precision agriculture discussed in the previous section there was an actual implementation of camera equipped robots that can cover 5 acres each day and collect big datasets for continuous development using solar energy. It works for specific types of crops now, however there is a room for improvement to adapt machine learning algorithms to make them work in any kind of environment. 

In addition to this, to quantify the thickness of peat and measure the carbon store of tropical peatlands, machine learning was applied to characteristics collected from remote sensing data. Maps that are going to predict the risk of fire are expected to be developed in the nearest future using advanced machine learning techniques.

Regarding CO2 sequestration, for more than two decades, a Norwegian oil firm has effectively sequestered CO2 from an offshore natural gas field in a saline aquifer. Recently, machine learning approaches, as well as computer vision systems for emissions detection, have been utilized to monitor potential CO2 leakage from wells and finding most reliable sites for the sequestration.

Why is this study important? This study gives an overview of how machine learning can be used to make a meaningful contribution in the fight against climate change, whether through effective engineering or research. Therefore, it provides valuable information and potential ideas for data scientists, machine learning enthusiast, investors, researchers that can be used to prevent catastrophic consequences.

The big picture: Climate change is a complex issue that requires a multidisciplinary approach to be solved. Greenhouse gases emissions are one of the main reasons behind global changes in temperatures, precipitation, ice glacier masses loss, and frequent fires. Mitigation of those gases requires fundamental changes in the number of sectors that includes transportation, construction, electricity systems, and industries. Unfortunately, the majority of the solutions are computationally expensive to be implemented due to big amounts of data, such as for example some climate models, where conventional statistical methods don’t work. Machine learning methods and techniques can be used to address those issues since they are less computationally expensive and more accurate. 

Citation: Rolnick, D., Bengio, Y., Chayes, J., Creutzig, F., Platt, J., Hassabis, D., Ng, A., Gomes, C., Kording, K., Mukkavilli, K., Sherwin, E., Maharaj, T., Luccioni, A., Brown, A. W., Jaques, N., Dupont, N., Ross, A. S., Sankaran, K., Lacoste, A., … Donti, P. L. (2019, November 5). Tackling Climate Change with Machine Learning. https://arxiv.org/. Retrieved December 15, 2021, from https://arxiv.org/pdf/1906.05433

Aerosols are Controlled by the Same Processes that Modulate Stable Isotope Ratios of Ice

Concomitant variability in high-latitude aerosols, water isotopes and the hydrologic cycle

Bradley R. Markle, Eric J. Steig, Gerard H. Roe, Gisela Winckler,  Joseph R. McConnell

Summarized by Mauricio Hollis, who is an Environmental Geology major that is also minoring in Environmental Studies at Binghamton University in New York.  He is currently a senior who will graduate in Spring 2022.  At the moment he is applying to graduate schools and plans to do research on paleoclimate.  In the future he plans to work in academia and become a professor.  Some of his hobbies aside from geology are hiking, skiing, and fitness.

What data were used?  There were three ice cores used in this article that interpreted the relationship between high latitude aerosols and water isotopes.  They were from the West Antarctic Ice Sheet Divide ice core (WDC), the Greenland Ice Core Project (GRIP), and the European Project for Ice Coring in Antarctica (EPICA) from Dome Concordia (EDC).  There were also marine sediment cores used to compare with Antarctic dust records, two being from the South Atlantic downwind of South American dust sources, and more marine sediment cores that were located just north of the WDC in the South Pacific. 

Methods:  Concentrations of δ18O, non-sea-salt calcium (nssCa), and sea-salt sodium (ssNa) were collected and analyzed from the WDC.  They were first compared on a time scale ranging from 6 thousand years ago to 67 thousand years ago comparing water isotopes with aerosol records.  Temperature, saturated mixing, δ18O, and relative atmospheric aerosol concentrations were then plotted against Southern Hemisphere latitudes.  On these figures there are three different lines representing the different trends between the Last Glacial Maxima (LGM), modern temperature, and modern temperature cooled by 3°C.  The models for the relation between high-latitude water isotopes and sea-salt amplification were then compared.  Using data from GRIP and WDC, there was a comparison of their amplifications of nssCa against δ18O concentrations.  Dust aerosol records are then compared from the WDC and EDC with marine sediment records to plot the amplification factors against the past 40 thousand years.  Lastly, dust amplification against all latitudes is predicted through the use of a rainout model.

Figure 1a. Graph comparing ssNa, nssCa, and water isotope values vs time. Shows a negative exponential correlation between aerosols and δ18O. From Markle et al. (2018), Nature Geoscience.

Results:  It was found using these data that the hydrological cycle is the primary modulator of variability for dust, sea salt, and water isotopes.  Based on Figure 1A (right) there is evidence of a negative exponential relationship between water isotopes and aerosol concentrations for ssNa and nssCa.  This is indicative that as mean global temperatures decrease and more ice is formed, δ18O water isotope values see a decrease in concentration while dusts see an increase.  It is observed that there is overall less nssCa than ssNa.  This is explained by the terrigenous source of nssCa being 20°N of the marine source for ssNa resulting in lower concentrations of nssCa from 60°S-90°S due to a longer path of travel.

It is also observed that during the LGM there were higher concentrations of dust than during warmer periods of climate.  The data indicate there is evidence of smaller glacial-interglacial change for ssNa than nssCa. This is again a result of a shorter rainout pathway for marine aerosols than terrestrial aerosols.  It was also observed that δ18O isotope values from Greenland and Antarctica are very similar as they both show a negative exponential relationship with nssCa concentration amplification factor.  This is significant because they are on opposite sides of the globe with different dust sources and different regional conditions.  The data displayed for WDC and EDC show at some times, 10-100-fold amplification in dust than that collected for marine dust, which shows an amplification of 2-3-fold.  Lastly, fthe data indicate that amplification factors at the poles and higher latitudes is exponentially higher than at lower latitudes.

Why is this study important?  This study carries a lot of significance because it concludes that dust and water isotopes are both controlled by the same process, the hydrological cycle.  This has importance because it is necessary to understand the patterns of aerosol changes to further understand past radiative forcing.  

The Bigger Picture: This study disproves the theory that dust source emissions were a primary driver in ice-core records of aerosol, but rather changes in aerosol concentration at different latitudes is a result of the rainout effect.  It provides us with relevant results that can be further used to interpret how climate has changed since the LGM. 

Citation: Markle, B.R., Steig, E.J., Roe, G.H. et al. Concomitant variability in high-latitude aerosols, water isotopes and the hydrologic cycle. Nature Geoscience, 11,853–859 (2018). https://doi.org/10.1038/s41561-018-0210-9

Reconstructing the Eocene’s Climate System

Reconstructing Eocene Eastern Indian Ocean Dynamics Using Ocean-Drilling Stratigraphic Records

Ke Xu, David De Vleeschouwer, Maximilian Vahlenkamp, Renchao Yang, and Honghan Chen

Summarized by Olivia Cashimere, who is pursuing her Masters in Geology at Binghamton University. She is currently in her first year, and after graduation would like to work at a research museum. When she is not studying she enjoys hiking, traveling, and a variety of art mediums.

What data were used: This study focuses on two ocean drill hole archives, Ocean Drilling Program Sites 762C and U1514, located within the Eastern Indian Ocean. This study is concentrating on a 22 million year time span within the Eocene Epoch. This time period was leading up to a transition from a greenhouse to ice house climate conditions during the Cenozoic. During this time not much continental ice is seen around the globe, so not many ice related positive feedbacks are seen throughout the Eocene however, strong correlation is found between Milankovitch cycles and the climate changes. This study also uses previous studies on paleomagnetism and biostratigraphy to determine ages, and to check for ambiguity within the record.

Methods: This data collected from ODP Sites 762C and U1514 was applied to orbital scale dynamics using existing sedimentary sequences with biostratigraphy, radio-isotope dating, and magnetostratigraphy. Then stratigraphic interpretation from Site 762C is combined with an existing age depth model from Site U1514 to create a high resolution timescale for the Eocene. Downhole wireline logging with a natural gamma radiation spectrometer was also used to provide elemental data of potassium, thorium, and uranium. These help determine mineral composition, humid vs. dry environments, and astronomically forced climate signals. Using the log10 (Th/K) data a time series analysis was developed, omitting any gaps from poorly recovered core in the data. Previous studies done on Hole 762C provides data and analysis on the magnetostratigraphic record and calcareous nannofossil biostratigraphy. This data was combined to create a reconstruction of the Eocene timescale.

Results from the study showing the analyses in six panels.
Interpretation of ODP Site 762C 180-289.75 meters below sea floor in the core. The solid purple line at 249.41 mbsf, is a paleo magnetic anchor point at the Chron boundary. The blue sawtooth line (a) is the log10(Th/K) and the green line (b) is a 100 kyr filter, while the red is a 405 kyr filter. (c) Next is the FFT spectrogram of the log10(Th/K) depth series and (d) the power spectrum of the log10(Th/K) depth series. (e) The black sawtooth line is the tuned log10(Th/K) time series while (f) the green line is the 100kyr filter and red is the 405 kyr filter. (H) Next is the evolutionary FFT spectrogram of log10(Th/K) time series and (i) the power spectrum of the log10(Th/K) time series.

Results: The log10 (Th/K) analysis variability is found in cyclic patterns that roughly match with age depth, with an important note that there are four major gaps found in core recovery. Spectral analysis and depth-series provides sufficient data that sediment accumulation is steady, and power spectrum analysis identifies time series, prominent cycles, and peak frequencies exceeding 99% confidence level. Using the biostratigraphic markers previously found, the orbital tuning for Site 762C, correlated with a 405 kyr eccentricity cycle, and the paleomagnetic data was revamped to match boundaries, however, because of poor core recovery much of this data is still ambiguous and will require further studies. However with this record it reduced the number of gaps from six to four. This allowed for a supported hypothesis overall, and the combined research created an Eocene astronomical timescale that has correlated collected data across various other research methods.

Why is this study important? This study is focusing on key forcing factors that could have changed the climate dramatically during the Eocene. During this time period it is believed that there was very little continental ice across the globe, so any positive feedback from these ice sheets would be mostly nonexistent. However, we must have forcing factors that effect the environment. This study is theorizing on the possibility of astronomical forcing in deep-water circulation in the western North Atlantic. This study also identifies obliquity as the driver of Eocene climate conditions. This can be applied to current day climate systems to theorize about the current global climate warming and its effects of the planet. 

The big picture: The obliquity of Earth’s rational axis plays an important role in the deep water circulation and the movement of sediment supply. Low obliquity can be found to coincide with the cooling of ocean temperatures, and high obliquity with its warming. This idea can be used throughout may areas of study to increase our knowledge of how the Earth’s rotation changes our climate systems, and how sediments have been transported through ocean systems in the past. 

Citation: Xu, K., De Vleeschouwer, D., Vahlenkamp, M., Yang, R., & Chen, H. (2021). Reconstructing Eocene Eastern Indian Ocean Dynamics using ocean‐drilling stratigraphic records. Paleoceanography and Paleoclimatology36(2). https://doi.org/10.1029/2020pa004116 

 

The first sea-surface temperature model based on Porites astreoides coral skeletons

The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean

N.S. Pereira, A. N. Sial, R. Frei, C. V. Ullmann, C. Korte, R. K. P. Kikuchi, V. P. Ferreira, K. H. Kilbourne

Summarized by Harry Janoff, who is currently a senior at Binghamton University and is majoring in Geology. After graduating from Binghamton University, Harry plans to find entry-level work in order to receive more field experience. He is unsure if he will return to grad school right now but he has definitely considered it and definitely does not want to go until he has more experience in the field. When he is not studying Geology, Harry loves to play chess and the violin.

What data were used: In their research, Pereira and their team use aragonitic coral skeletons to create records of strontium to calcium ratios and records of d18O and d13C in order to determine ancient environmental conditions of the ocean. They also used the coral’s skeletons to create the first ever d18O calibrations based on sea surface temperatures for the Porites astreoides coral species.

Methods: Pereira and their team collected Porites astreoides samples from the Rocas Atoll, located about 270 kilometers from the northeast coast of Brazil, because it is the only atoll present in Western region of the South Atlantic ocean. They collected series of sea surface temperature data for the region through the use of the NOAA pathfinder AVHRR between October 2012 and October 2013 and collected samples of P. astreoides coral from the atoll’s Cemiterio tide pool during July of 2013. The Porites samples were then cut into 5 mm thick samples and from those, carbonate samples were collected at .5 mm intervals.

The geochemical analysis of these coral samples was performed at the University of Copenhagen and involved the use of a Micromass IsoPrime mass spectrometer to measure the d18O and d13C isotopes. Coral Sr/Ca ratios were measured using a Perkin Elmer Optima 7000 DV ICP-OES and the samples were measured at a calcium concentration of ~10 mg/g.

Results: The researchers found that the two isotopes had abundance rates of 0.09‰ for d13C and 0.10‰ for d18O. They also discovered that the Sr/Ca ratios and isotope cycles displayed seasonality between 2001 and 2013. The Sr/Ca values for the coral varied between 8.86 to 9.15 mmol/mol and the mean value for the samples was 8.98 mmol/mol. d13C values for this research ranged from -1.38% to 1.05‰  with a mean value of 0.07‰ and the annual cycle for d13C contained the most positive d13C values in September and the most negative values in April or May. d18O values range from -4.26 to -3.69% and their mean value was -3.96‰. Unlike the d13C values, the d18O values were found to be  highly consistent overall, but there was a small increase in more-positive values during the years of 2006 and 2007.

Graphs of data that indicate sea surface temperatures and other surface ocean conditions as obtained from the Porites corals.
The data collected from 2001 to 2013 using the Porites coral was plotted into graphs and includes data on d13C concentrations, d18O concentrations, Sr/Ca values, sea surface temperatures, and rainfall in millimeters. The d18O, Sr/Ca and SST data are all cyclical and contain peaks towards the beginning of years and low points during the middle of years. d13C is the only outlier because its peaks are in the middle of years while its low points are closer to the beginning of years. The highest amount of rainfall was recorded around the middle of 2007 and this peak correlates to one of the largest sea surface temperature dips and a dip in Sr/Ca and d18O.

Why is this study important? This study is incredibly important because knowing the cycles in d13C values and consistency of the d18O values allows us to begin piecing together the conditions where these coral skeletons formed. Pereira and their team’s research was also the first to relate these Porites astreoides values to sea surface temperatures, which will allow us to learn even more about, and maybe fully understand, the climate when these corals were formed. This study also creates links between d13C concentrations and sea surface temperature through the coral skeletons. By understanding the conditions under which these coral formed, we are able to understand climate cycles that have occurred within the Southern Atlantic ocean. Using that information, we may be able to interpret what the climate of this region was like in the past and what it may become in the future. 

Citation: Pereira, N. S., Sial, A. N., Frei, R., Ullmann, C. V., Korte, C., Kikuchi, R. K. P., … & Kilbourne, K. H. (2017). The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean. Journal of South American Earth Sciences77, 276-285.