Article
Environmental Sciences
Haruka Takagi, Katsunori Kimoto, Tetsuichi Fujiki
Summary: Photosymbiosis is a key feature in planktonic foraminifera, where a single host can have thousands of symbiont cells, making photosynthesis a hotspot for primary production. Understanding the photosynthetic activities of symbionts is crucial for interpreting geochemical proxies recorded in foraminiferal tests. The relationship between the fluorescence-based photosynthetic rate and carbon assimilation rate was studied in two species, showing a significant positive correlation but different regression slopes. The high apparent electron requirement for carbon assimilation observed may be due to the use of respiratory carbon.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Geochemistry & Geophysics
Maciej M. Telesinski, Mohamed M. Ezat, Francesco Muschitiello, Henning A. Bauch, Robert F. Spielhagen
Summary: Changes in ocean circulation play a crucial role in centennial-to-millennial scale climate variability during the last deglaciation. Through sediment records from the Nordic Seas, researchers studied radiocarbon ventilation ages to reconstruct past variations in watermass overturning. Variability in ventilation ages among different records suggest regional shifts in deep convection and emphasize the importance of using uniform material for reconstructing bottom water ventilation histories.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Environmental Sciences
Chen Kenigsberg, Danna Titelboim, Sarit Ashckenazi-Polivoda, Barak Herut, Michal Kucera, Yuval Zukerman, Orit Hyams-Kaphzan, Ahuva Almogi-Labin, Sigal Abramovich
Summary: The study found that the Amphistegina lobifera performed optimally at 39 psu and 25 degrees C, but its growth was significantly reduced under higher salinities and temperatures. In contrast, Peneroplis showed higher tolerance to elevated temperature and salinity, potentially leading to a shift in dominant species under further increases in salinity and temperatures.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Barbel Honisch, Carina R. Fish, Samuel R. Phelps, Laura L. Haynes, Kelsey Dyez, Kate Holland, Jennifer Fehrenbacher, Katherine A. Allen, Stephen M. Eggins, Joaquim Goes
Summary: The study found significant differences in B/Ca ratios and isotopic composition recorded by different foraminifer species grown under identical environmental conditions, possibly due to species-specific rates of symbiont photosynthesis and habitat depth. Although light experiments showed that symbiont photosynthesis elevates pH and/or delta B-11 in the calcifying microenvironment of all three foraminifer species, FRRF, Chl. a, and symbiont abundance data were relatively uniform among the three species and did not consistently scale with intrashell B/Ca or with observed offsets.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Environmental Sciences
P. Kiss, L. Jonkers, N. Hudackova, R. T. Reuter, B. Donner, G. Fischer, M. Kucera
Summary: Planktonic foraminifera play a crucial role in the marine calcite budget and CO2 uptake. Shell flux is a key factor in regulating calcite flux variability on intra-annual timescales, while shell mass variability can be as important as shell flux on inter-annual timescales.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Geology
Anat Ash-Mor, Ahuva Almogi-Labin, Vincent M. P. Bouchet, Laurent Seuront, Tamar Guy-Haim, Zvi Ben-Avraham, Revital Bookman
Summary: This study investigates the transport of continental shelf sediments to the deep ocean in simulated high flow conditions. Results show that at a velocity of 80 cm/s, different shapes of larger benthic foraminifera shells efficiently suspend and transport in large quantities throughout the water column, and 80 cm/s is also the threshold for the formation of thick coarse deposits in the slope sedimentary record.
Article
Geology
E. Wolfgring, M. Wagreich, J. Hohenegger, K. Boehm, J. Dinares Turell, S. Gier, B. Sames, C. Spoetl, S. Jin
Summary: This study examined the cyclostratigraphy and paleoenvironments of pelagic deposits of the northwestern Tethys in the Upper Cretaceous Postalm section in Austria. The section displays rhythmic deposits from Santonian to late Campanian age, with distinct transitions and characteristics identified through biostratigraphy and isotope stratigraphy. The analysis of proxies in the upper section part revealed cycles spanning mid to upper Campanian, providing valuable insights into the geological history of the region.
CRETACEOUS RESEARCH
(2021)
Article
Marine & Freshwater Biology
Mattia Greco, Raphael Morard, Michal Kucera
Summary: The interactions of Neogloboquadrina pachyderma with the local eukaryotic pelagic community are mainly dominated by diatoms, but other groups such as Crustacea and Syndiniales are also present. The high abundance of Syndiniales suggests that these parasites could infect N. pachyderma and play an important role in its population dynamics. Furthermore, the non-specific association with algae, regardless of depth and occurring below the photic zone, indicates that diatom-fueled marine aggregates may be the main interaction substrate of N. pachyderma.
JOURNAL OF PLANKTON RESEARCH
(2021)
Article
Multidisciplinary Sciences
Debora S. Raposo, Rebecca A. Zufall, Antonio Caruso, Danna Titelboim, Sigal Abramovich, Christiane Hassenrueck, Michal Kucera, Raphael Morard
Summary: The invasive marine protist A. lobifera has a strong tolerance to environmental conditions in the Mediterranean Sea, and its success is related to high dispersal ability and suppression of sexual reproduction. This discovery highlights the cost of invasion in marine protists, as the success of A. lobifera in the Mediterranean comes at the expense of abandoning sexual reproduction.
SCIENTIFIC REPORTS
(2023)
Article
Paleontology
Sandro M. Petro, Maria A. G. Pivel, Joao C. Coimbra
Summary: This study aims to identify minor changes in the preservation of foraminiferal assemblages in the supra-lysoclinal zone, using Late Quaternary samples from the Pelotas Basin continental slope. The best preservation indexes are associated with North Atlantic Deep Water (NADW) influence, while periods of relative greater dissolution are linked to the advance of Upper Circumpolar Deep Water (UCDW). Marine Isotope Stages (MIS) 5 and MIS 1 show the best preservations, with MIS 4, 3, and 2 exhibiting relatively poorer preservation.
MARINE MICROPALEONTOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Se Hyeon Jang, Seong In Na, Moo Joon Lee, Yeong Du Yoo
Summary: The dinoflagellate family Suessiaceae is a group of widely distributed species in marine and freshwater ecosystems, including some that cause red tides. Classifying them within the family is challenging due to limitations of existing molecular markers. This study evaluated mitochondrial genes as new markers and confirmed their effectiveness in revealing genetic diversity within the family Suessiaceae.
MOLECULAR PHYLOGENETICS AND EVOLUTION
(2022)
Editorial Material
Biochemistry & Molecular Biology
Stephanie Porter
Summary: The study demonstrates that a new partnership between a protist and an algal symbiont can rapidly evolve to overcome initial incompatibility and adapt to environmental challenges.
Article
Environmental Sciences
Xiaolin Zhu, Liju Tan, Ting Zhao, Wenqiu Huang, Xin Guo, Jiayin Wang, Jiangtao Wang
Summary: The toxic effects of nano-ZnO and GQDs on dinoflagellate Gymnodinium were investigated. Nano-ZnO had slight effects on algal cell growth, while the growth inhibition of Gymnodinium increased with increasing GQDs concentration. Both nanoparticles induced accumulation of reactive oxygen species and activated intracellular antioxidant defense system. The combined exposure of nano-ZnO and GQDs showed decreased inhibitory effects compared to GQDs alone.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Biology
Alix E. Matthews, Than J. Boves, Katie L. Percy, Wendy M. Schelsky, Asela J. Wijeratne
Summary: Microscopic symbionts, such as feather mites, pose challenges in high-throughput sequencing (HTS) studies due to their small size and minimal DNA yields. This study used a strategic Pool-Seq approach to overcome these challenges and assess genetic diversity in feather mites. The results showed that samples containing multiple mites had more sequencing reads mapping to the mite reference genome than samples with only a single mite. The genetic structure of mite infrapopulations was primarily determined by individual hosts, indicating evolutionary processes at the infrapopulation level. This work highlights the importance of both individual-level and infrapopulation-level sequencing in understanding host-symbiont coevolution.
Article
Multidisciplinary Sciences
Ryuichi Koga, Masahiko Tanahashi, Naruo Nikoh, Takahiro Hosokawa, Xian-Ying Meng, Minoru Moriyama, Takema Fukatsu
Summary: Microbial symbioses play a significant role in diverse organisms, with long-lasting associations leading to symbiont genome erosion and potential extinction. The discovery of a host protein essential for sustaining symbiosis in Plataspid stinkbugs sheds light on how intimate host-symbiont associations can be maintained over evolutionary time. In addition to the host's guardian protein, the symbiont's molecular chaperone, GroEL, is overproduced in capsules, compensating for the symbiont's eroding functionality.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Environmental Sciences
Jung-Woo Park, Yejin Kim, Kwan-Woo Kim, Amane Fujiwara, Hisatomo Waga, Jae Joong Kang, Sang-Heon Lee, Eun-Jin Yang, Toru Hirawake
Summary: The northern Bering and Chukchi seas are biologically productive regions, but recent environmental changes have had unprecedented effects. This study investigated the dominant phytoplankton communities and their contributions to primary production in these regions. The results showed that diatoms and phaeocystis were dominant phytoplankton communities in 2016, while diatoms and Prasinophytes were dominant in 2017. Small phytoplankton contributed differently to total primary production in the two years. Furthermore, there were distinct biochemical differences between small and large phytoplankton.
Article
Oceanography
Jong-Ku Gal, Sun-Yong Ha, Jisoo Park, Kyung-Hoon Shin, Dongseon Kim, Nan-Young Kim, Sung-Ho Kang, Eun Jin Yang
Summary: Satellite observations and modeling data show an increase in net primary production in the Arctic Ocean due to retreating sea ice and warming, with under-ice blooms becoming more important. The role of sea-ice algae in these blooms is still unknown due to limited observations.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Microbiology
Ping Sun, Yuyu Liao, Ying Wang, Eun-Jin Yang, Nianzhi Jiao, Youngju Lee, Jinyoung Jung, Kyoung-Ho Cho, Jong-Kuk Moon, Dapeng Xu
Summary: This study explored the diversity, community composition, and co-occurrence networks of pico-sized haptophytes in the changing Arctic Ocean. The results showed higher alpha diversity in the surface water compared to the subsurface chlorophyll maximum layer. Water temperature was identified as the primary factor shaping community compositions. The surface water networks were found to be more stable than the subsurface chlorophyll maximum networks.
Article
Environmental Sciences
Youngju Lee, Jinyoung Jung, Tae Wan Kim, Eun Jin Yang, Jisoo Park
Summary: In the Amundsen Sea, global warming has accelerated ice melt and affected various ocean properties. A study on phytoplankton growth found that light limitation plays a role in determining phytoplankton abundance and biomass. Different responses to light and sinking rates of each species were found to control the distribution of phytoplankton in the surface layer.
ENVIRONMENTAL RESEARCH
(2022)
Article
Plant Sciences
Jin Hee Ok, Hae Jin Jeong, Hee Chang Kang, Sang Ah Park, Se Hee Eom, Ji Hyun You, Sung Yeon Lee
Summary: Water temperature has a significant impact on the growth and ingestion rates of the planktonic organism S. gracilenta, with feeding shifting its optimal temperature for growth from 20 to 25 degrees C. Additionally, global warming may affect the distribution of S. gracilenta.
Article
Oceanography
Jinyoung Jung, Youngju Lee, Kyoung-Ho Cho, Eun Jin Yang, Sung-Ho Kang
Summary: The distribution of dissolved organic carbon (DOC) in the western Arctic Ocean during the summer season was investigated. The concentration and contribution of riverine DOC in the surface layer of the Chukchi Borderland/northern Chukchi Sea region were higher than those in the East Siberian Sea/Mendeleyev Ridge region. Marine DOC was the dominant component in both regions, but the East Siberian shelf/slope region had higher concentration and contribution of marine DOC, which was attributed to high bacterial abundance and nutrient supply from the deep layer.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Geosciences, Multidisciplinary
Jun-Oh Min, Sung-Han Kim, Jinyoung Jung, Ui-Jung Jung, Eun Jin Yang, SangHoon Lee, Jung-Ho Hyun
Summary: The study reveals the tight coupling between glacial meltwater and heterotrophic bacterial production on the Getz Ice Shelf in the Antarctic Amundsen Sea, with higher BP in the eastern Getz Ice Shelf mainly attributed to meltwater-derived dissolved organic carbon. This suggests that warming-induced glacier melting may weaken carbon sequestration efficiency in Antarctic coastal waters by stimulating heterotrophic metabolism.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Marine & Freshwater Biology
Jin Hee Ok, Hae Jin Jeong, An Suk Lim, Ji Hyun You, Yeong Du Yoo, Hee Chang Kang, Sang Ah Park, Moo Joon Lee, Se Hee Eom
Summary: In order to investigate the influence of eutrophic deep waters on red-tide outbreaks, water samples were collected from different depths in the South Sea of Korea, and the growth rate of major red-tide dinoflagellates was examined. The results showed that the growth rates of these species rapidly increased and reached saturation at certain dissolved inorganic nitrogen concentrations. The study also revealed that the intrusion and retreat of deep waters, as well as solar insolation, can affect the outbreaks of harmful red tides.
Article
Marine & Freshwater Biology
Ji Hyun You, Hae Jin Jeong, Jin Hee Ok, Hee Chang Kang, Sang Ah Park, Se Hee Eom, Sung Yeon Lee, Nam Seon Kang
Summary: Water temperature is a key factor in the growth and distribution of mixotrophic dinoflagellates. This study investigated the growth rate of Biecheleria cincta BCSH1005 and its distribution under different water temperature conditions. It was found that B. cincta grew mixotrophically at temperatures between 15 and 25 degrees C, but did not grow autotrophically at any tested temperature. The spatiotemporal distributions of B. cincta in Korean coastal waters were also studied using real-time polymerase chain reaction. The results suggest that trophic mode and water temperature play important roles in the survival and distribution of B. cincta.
Article
Plant Sciences
An Suk Lim, Hae Jin Jeong
Summary: The study found that over the past 17 years, sea surface temperature in the territorial sea of the Republic of Korea has increased, while nutrient concentrations have declined, and primary production (PP) of phytoplankton did not show a specific temporal trend, with the highest daily PP in the western South Sea region. The maximum PP in Korean territorial waters accounts for 0.03% of the global PP, providing insights into the ecosystem of the studied region.
Article
Marine & Freshwater Biology
Moo Joon Lee, Hae Jin Jeong, Yeong Du Yoo, Sang Ah Park, Hee Chang Kang
Summary: This study examines the interactions between Gyrodinium jinhaense and G. moestrupii and copepods. By determining the ingestion rate of Acartia spp. copepods on these three Gyrodinium species, the researchers found that the maximum ingestion rates on G. jinhaense and G. dominans were similar and higher than that on G. moestrupii. The ingestion rates on these Gyrodinium species were lower than some other heterotrophic dinoflagellates.
Article
Plant Sciences
Jin Hee Ok, Hae Jin Jeong, An Suk Lim, Hee Chang Kang, Ji Hyun You, Sang Ah Park, Se Hee Eom
Summary: Exploring the mixotrophy of dinoflagellate species is essential for understanding red-tide dynamics and dinoflagellate evolution. Only two species in the Karenia genus have been investigated for their mixotrophic ability. However, the mixotrophy of the other species remains unknown.
Article
Plant Sciences
Hee Chang Kang, Hae Jin Jeong, An Suk Lim, Jin Hee Ok, Ji Hyun You, Sang Ah Park, Se Hee Eom
Summary: The mortality rate of red-tide dinoflagellates is influenced by predation, which is a crucial factor affecting their population dynamics. Several common heterotrophic protists can feed on A. granifera, but their ingestion and growth rates on this prey species are relatively low. Therefore, the low mortality rate of A. granifera may contribute to its bloom formation.
Article
Marine & Freshwater Biology
Jin Hee Ok, Hae Jin Jeong, Kyung Ha Lee, Hee Chang Kang, Ji Hyun You, Sang Ah Park, Se Hee Eom, Kyeong Ah Seong
Summary: In red-tide dynamics, one species often dominates microalgal communities after intense competition among several species. In Korean waters, red tides are formed by Prorocentrum donghaiense, Tripos fusus, Alexandrium fraterculus, and Margalefidinium polykrikoides, which can result in massive fish kills and economic losses. The growth of one species can be inhibited by high abundance of the others, indicating density-dependent inhibition.
Article
Plant Sciences
Ji Hyun You, Jin Hee Ok, Hee Chang Kang, Sang Ah Park, Se Hee Eom, Hae Jin Jeong
Summary: This study investigated the mixotrophic ability of several species in the Scrippsiella genus and found that only S. acuminata exhibited mixotrophy, while the other five species did not.