Fieldwork in Kikaijima (9/29-10/2)

こんにちは！D2のYangerです！

I just got back from a field trip to Kikaijima with Professor Hirabayashi. Kikaijima is a small island in Kagoshima Prefecture, east of Amami. Besides being known for its sugar cane and sesame, the island is also famous for its uplifted coral reefs and was recently designated as a Japanese geopark. As we approached the island by air, we could clearly see the classic spur-and-groove formations of its coral reefs.

Our main mission this time was to survey limestone outcrops exposed during excavation for an underground dam. We were joined by Professor Marc Humblet from Nagoya University, an expert on coral and limestone assemblages. With his help, we identified fossils of corals, foraminifera, brachiopods, and other organisms preserved in the limestone. These fossils offered clues about the water depths and environments in which they originally lived. We even found a well-preserved barnacle fossil protruding from the rock face!

We spent two days at the site documenting and sampling the specimens we found in the rock. After long days working under the sun, we were rewarded with beautiful sunsets.

In addition to examining the outcrops, we also had the chance to inspect rock cores collected before construction began. The cores were stored in the gym of an old school, where rows upon rows of boxes filled the space. As we examined the cores and identified sections containing corals, foraminifera, and crustose coralline algae (CCA), we could trace how the island's environment had changed over time.

  

On our final day, we drove around the island to sample groundwater from springs. Professor Hirabayashi explained that our lab has been regularly monitoring the geochemical composition of Kikaijima's groundwater for several years. By using radiocarbon as a tracer, these measurements help us understand how groundwater moves and changes beneath the island.

In just four days, I got a glimpse of the exciting research being conducted on this coral island. A huge thank you to Professor Humblet for helping us identify the various organisms preserved in the limestone and explaining what they can tell us about the island's past environments. I'm also very grateful to Professor Hirabayashi for organizing the trip and teaching me so much about Kikaijima!

New Papers (AGU, etc.) 2026/09/29~2026/10/05

 

Geochemistry, Geophysics, Geosystems

1. Pre-Eruptive Volatiles and Magma Storage Depth for the 2018 Eruption at Mount Veniaminof, Alaska

    E. G. Huggins, P. Ruprecht, M. Loewen, M. Gavrilenko, R. J. Bodnar, M. Harlaux

 

Geophysical Research Letters

2. Cosmogenic ¹⁰Be as a Tracer for Recent Heliospheric Encounters With Interstellar Cold Clouds and Nearby Supernovae

    Anna Nica, Merav Opher, Jesse A. Miller, Jennifer L. Middleton, Joe Giacalone

3. Water Storage Capacity Dynamics in Drained Boreal Peatlands: Responses to Rewetting and Climate Change

Shokoufeh Salimi, Behshid Khodaei, Hjalmar Laudon

4. Climate Change Induced Seasonal Amplification of the Indian Ocean CO₂ Sink

    A. P. Joshi, Kunal Chakraborty, V. V. S. S. Sarma, Prasanna Kanti Ghoshal, B. Sridevi, Zouhair Lachkar

5. Asynchronous Changes in Tempo-Spatial Patterns of the Younger Dryas Hydroclimate in Northeastern China

   Sihan Sun, Yukun Zheng, Yue Wang, Jun Cheng, Yiyin Li, Hongyan Liu, Ulrike Herzschuh

6. Dead Sea Warming and the Origin of Salt Giants

   E. Guillerm, T. K. Lowenstein, V. Gardien, F. Bärenbold, D. Bouffard, A. Brauer, F. Caupin

7. Record-Breaking Humid Heat in Northern China During Summer 2025 Driven by Kuroshio–Oyashio Extension SST Anomalies

   Wenyue He, Huopo Chen, Zhicong Yin, Fei Xie

8. Divergent Influences of Oceanic Western Boundary Currents on Weak and Strong Tropical Cyclones

   Wenting Lou, Tongya Liu, Jiacheng Hong, Yi-Peng Guo, Han Zhang, Dake Chen

 

Paleoceanography and Paleoclimatology

9. Simulated Ocean Oxygen Under Miocene Boundary Conditions

   James R. Berg, David K. Hutchinson, Katrin J. Meissner, Benoît Pasquier, Mark Holzer, Alexandra Auderset

10. Chemostratigraphic Constraints on Oligocene–Miocene Sedimentation and Hiatus Formation at IODP Site U1516, Mentelle Basin: Implications for Deep-Water Circulation in the Eastern Indian Ocean

   Tianqi Sun, Christophe Colin, Zhaokai Xu, Arnaud Dapoigny, Rosella Pinna-Jamme, Dhongil Lim, Gang Hu, Fengming Chang, Hongjin Chen, Wei Wang, Qingchao Fan, Tiegang Li

 

Climate of the Past

11. Ocean warming caused by Late Ordovician glacial onset in a coupled climate-ice sheet simulation

   Yudong Sun, Yonggang Liu, Jiacheng Wu, Kai Man, Haonan Yu, Shuai Yuan, Yizhang Liu, Yue Liu, Qi Cui, Qiang Wei, and Yongyun Hu

12. Holocene-like summer climate during Marine Isotope Stage 11 in northwestern Greenland

    John Michael N. Aguilar, Elizabeth K. Thomas, Diana S. Aga, Paul R. Bierman, Jason P. Briner, Isla S. Castañeda, and Andrew J. Christ

Seawater, Sea Squirts, and Stories from Onagawa

こんにちは！D3のMiyaです！

I recently visited Onagawa to help Professor Tanaka and her students with fieldwork on hoya (sea squirts). Their research focuses mainly on cellulose analysis and DNA-based investigations, while my role was to help collect seawater for dissolved inorganic carbon (DIC), uranium/thorium (U/Th), and oxygen isotope (δ¹⁸O) analyses. I thought hoya is called sea pineapple, but realized only the commonly-eaten species マボヤ is called sea pineapple.

My first encounter with hoya was a few years ago, when I bought a sea pineapple at a supermarket in Otsuchi. It was my first time eating one, and I dissected it myself to prepare it. Cutting into it felt strangely like cutting into a heart—not that I’ve ever cut into one! This time in Onagawa, I got to see a wider variety of sea squirts as we sorted the different species by hand.

We sampled seawater both inside and outside the aquaculture farm, and the team also collected sediment samples. We even got to enjoy a bite of the fresh ones during sampling! 

Alongside the sampling, we sorted different species of hoya by hand, including マボヤ, エボヤ, and 白ボヤ. Working through the specimens gave me a closer look at the variety of sea squirts living in the area—something quite different from my usual work with abalone shells.

One evening, we had dinner with people working at Tohoku University’s Onagawa Field Center, part of the Graduate School of Agricultural Science. Over dinner, they shared their memories of the 2011 earthquake and tsunami.

One person recalled being on a research cruise with the coastal research center when the earthquake struck. After seeing the tsunami, he decided to sail farther offshore rather than return to land. He and his colleague ended up staying offshore for three days.

Hearing this account directly from someone who experienced it made a strong impression on me. Our visit was centered on collecting samples, but the conversations over dinner also offered a glimpse into the experiences of the people who live and work along this coast.

Thank you to Professor Tanaka, her students, and everyone at the Onagawa Field Center for welcoming me and sharing both their research and their stories. Also thank you Yosuke and Shishi for helping me with preparation and Yusuke for sponsoring the trip!

New Paper Nature and others (25/08/26 -01/09/26)

 

Science Advances

Near-term, geospatial opportunity for biomass carbon storage to address the wildfire and climate crises

Leah K. Clayton, Alexander S. Wyckoff, and Sinéad M. Crotty 

PNAS

Weak prestorm submesoscale sea surface temperature gradients conducive to tropical cyclone intensification

Hanrui Liu, Wenju Cai, Shoude Guan, +4 , and Zhengguang Zhang 

Rethinking the origin of life at seafloor hydrothermal vents

Benjamin M. Tutolo

Recent high-severity wildfires in a dry-conifer landscape are unprecedented over five centuries and foretell future forest loss

Andreas P. Wion, Jens T. Stevens, Jonathan D. Coop, +3, and Ellis Q. Margolis 

Major role for internal variability in tropical Pacific warming pattern over satellite era

Shang-Ping Xie  ,  Ayumu Miyamoto   Qihua Peng , and  Matthew T. Luongo

Nature Geoscience

Fan, CS., Sun, C., Xie, Z.  et al.  Hadley circulation drives material isolation and pole-to-pole teleconnection on Mars.  Nat. Geosci.  (2026). https://doi.org/10.1038/s41561-026-02090-2

Su, Y., Xu, Y., Zhang, X.  et al.  Disturbance characteristics and forest properties regulate surface warming and recovery across Europe.  Nat. Geosci.  (2026). https://doi.org/10.1038/s41561-026-02071-5

Liu, D., Jiang, F., Hu, K.  et al.  Warming potential of atmospheric black carbon modulated by particulate matter.  Nat. Geosci.  (2026). https://doi.org/10.1038/s41561-026-02068-0

Nature Communications

Fan, D., Duarte, CM, Wang, F.  et al.  The global distribution of macroalgal carbon burial in coastal sediments.  Nat Commun  (2026). https://doi.org/10.1038/s41467-026-77215-7

Namur, O., Charlier, B., Cartier, C.  et al.  Carbon distribution in planet Mercury from magma ocean evolution to graphite crust and core composition.  Nat Commun  17 , 9227 (2026). https://doi.org/10.1038/s41467-026-75458-y

Alcott, LJ, Mills, BJW, Bekker, A.  et al.  A nutrient control on oxygenation dynamics during Earth's Great Oxidation Episode.  Nat Commun  (2026). https://doi.org/10.1038/s41467-026-76597-y

Larsen, KMH, Eriksdóttir, G., Hansen, B.  et al.  Iceland-Faroe overflow revealed by in-situ observations.  Nat Commun  (2026). https://doi.org/10.1038/s41467-026-77220-w

Wang, S., Oppo, DW & Ummenhofer, CC Coupling of Pacific and Indian Ocean variability disrupted by 19th century volcanism.  Nat Commun  17 , 8572 (2026). https://doi.org/10.1038/s41467-026-76705-y

Pondom National Centre

Wang, H., Liu, J., Holden, J. et al. Climate warming drives thermal shocks and accelerated freshwater habitat fragmentation. Nat. Clim. Chang. (2026). https://doi.org/10.1038/s41558-026-02731-9

New Papers (Elsevier) 2026/08/25~2026/09/01

Earth and Planetary Science Letters

1. Eastern equatorial Pacific deep water Δ[CO₃^2-] changes during the last glacial maximum and early deglacial

    Matthew W. Schmidt, Brian J. Close, Jennifer E. Hertzberg, Franco Marcantonio

2. Full-waveform tomography of southeastern Tibet: Evidence for dual crustal low-velocity zones and hybrid tectonic processes

    Xinyu Jiang, Xiaodong Song, Xuezhen Zhang, Haoyu Xu, Xingchen Wang, Bin He, Hejun Zhu

Quaternary International

3. Sedimentary characteristics of the Ganges Submarine Delta and its response to chemical weathering during the Mid-Holocene

    Hongmin Wang, Lina Ai, Ashraf Ali Seddique, Bingjie Sun, Hui Zhang, Xiaoyan Li, Peng Cao, Kaikai Wu, Kunshan Wang, Shengfa Liu

4. Thermocline and paleo productivity changes off West Simeulue Island in relation to monsoonal hydroclimate since the Last Glacial Maximum

    Ryan Dwi Wahyu Ardi, Purna Sulastya Putra, Septriono Hari Nugroho, Winda Eka Mandiri Puteri, Khoiril Anwar Maryunani

5. Late Quaternary faunal remains as proxies for the human-environment relationships at San Esteban rockshelter in the northern Chihuahuan Desert, southwest Texas, USA

    Erika S. Blecha, Rolfe D. Mandel

6. Geomorphological dynamics at the coast: A sedimentary stratigraphy for Atlit-Yam, the earliest coastal village at the Eastern Mediterranean and its submerged landscape

    Vishal Kataria, Gilad Shtienberg, Isaac Ogloblin Ramirez, Roni Zuckerman-Cooper, Nimer Taha, Elle Grono, Marko Runjajić, Ehud Galili, Nicolas Waldmann, David E. Friesem