Article
Limnology
Natalya Evans, Juliana Tichota, James W. Moffett, Allan H. Devol
Summary: Nitrite is a crucial intermediate in the ocean's fixed nitrogen loss and accumulates in Oxygen Deficient Zones (ODZs). Recent research has found significant reoxidation of nitrite back to nitrate, impacting the global nitrogen cycle. Analysis of basin-scale data reveals extensive nitrite reoxidation across the Eastern Tropical North Pacific (ETNP) ODZ. The study also highlights metabolic switching points and high spatiotemporal variability in nitrite reoxidation. This analysis provides valuable insights into the recycling of fixed nitrogen in the ETNP.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Geochemistry & Geophysics
Kenneth M. Bolster, Maija I. Heller, Margaret R. Mulholland, James W. Moffett
Summary: The Eastern Tropical North Pacific (ETNP) is the largest oxygen deficient zone (ODZ) in the modern ocean. The distribution of dissolved Fe and Mn in the region shows certain patterns. Lateral advection of water from reducing shelf sediments is likely the main source of Fe distribution in the ETNP. Additionally, deep waters in the region are enriched in Fe, similar to other eastern boundary upwelling systems and the Arabian Sea.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Ecology
Rebeca Granja-Fernandez, Brenda Maya-Alvarado, Fabian A. Rodriguez-Zaragoza, Andres Lopez-Perez
Summary: Ophiuroidea is a marine group with wide distribution and particular lifestyles, making it suitable for exploring diversity partitioning in the ocean. However, there is still a lack of investigation and basic information on diversity in large areas such as the eastern tropical Pacific (ETP). This study examines the alpha, /3, and gamma-diversity patterns of Ophiuroidea in the ETP at multiple spatial scales. The results show significant differences in species composition at all spatial levels, and the variation in species composition is influenced by factors such as longitudinal and latitudinal gradients. This work represents the first attempt to analyze the distribution patterns of shallow-water Ophiuroidea from the ETP.
REGIONAL STUDIES IN MARINE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Alonzo Alfaro-Nunez, Diana Astorga, Lenin Caceres-Farias, Lisandra Bastidas, Cynthia Soto Villegas, Kewrin Macay, Jan H. Christensen
Summary: The research found a significant presence of microplastic pollution in both water samples and marine organisms in the Tropical Eastern Pacific and the Galapagos archipelago, with particles ranging from 150 to 500 μm in size being the most common. This study represents one of the first reports to simultaneously detect and quantify the abundance of microplastic particles and their impact on marine organisms in this region.
SCIENTIFIC REPORTS
(2021)
Article
Environmental Sciences
Joao B. Gusmao, Guillermo Luna-Jorquera, Marcelo M. Rivadeneira
Summary: A study on the relationships between biological trait diversity of seabird assemblages on islands in the southeastern Pacific Ocean and environmental factors revealed that physiographic characteristics of nesting islands and primary productivity in the surrounding waters have significant impacts on seabird trait diversity.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Geochemistry & Geophysics
D. S. Hardisty, T. J. Horner, N. Evans, R. Moriyasu, A. R. Babbin, S. D. Wankel, J. W. Moffett, S. G. Nielsen
Summary: This study investigated the rates and mechanisms of iodate reduction in the Eastern Tropical North Pacific using a shipboard tracer-incubation method. Results suggest that iodate reduction is limited to the oxycline, indicating restricted rates in the ODZ core with low oxygen concentrations, while incubations in areas with low oxygen levels did not show evidence of iodate reduction.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Environmental Sciences
Colette L. Kelly, Nicole M. Travis, Pascale A. Baya, Karen L. Casciotti
Summary: By analyzing N2O concentration and isotopologues in the eastern tropical North Pacific (ETNP), it was found that high N2O levels observed at some stations may be due to unique conditions supporting high rates of N2O production. Additionally, the study revealed different sources and potential mechanisms contributing to N2O cycling in oxygen deficient zones.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Multidisciplinary Sciences
Anya V. Hess, Alexandra Auderset, Yair Rosenthal, Kenneth G. Miller, Xiaoli Zhou, Daniel M. Sigman, Alfredo Martinez-Garcia
Summary: The oxygen content of the oceans has declined due to climate change, especially in oxygen-deficient zones. Climate warming simulations predict the expansion of these zones until at least 2100. The response of ocean oxygenation on longer timescales remains uncertain.
Article
Environmental Sciences
Shuai-Lei Yao, Jing-Jia Luo, Pao-Shin Chu, Fei Zheng
Summary: Since 1979, during the era of satellite-monitoring, the Pacific Walker circulation (PWC) has shown a significant strengthening and westward shifting, contradicting model projections in response to anthropogenic warming. The exact cause for the observed PWC intensification remains uncertain. Our study reveals that the North Atlantic-only SST warming and the tropical eastern Pacific-only SST cooling partly contribute to the decadal adjustment of the PWC. Furthermore, we find that the tropical Atlantic-eastern Pacific trans-basin SST gradients have had a dominant role in the PWC variations over the past century.
ENVIRONMENTAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Qiang Ma, Yusheng Qiu, Run Zhang, E. Lv, Yipu Huang, Min Chen
Summary: The study aimed to reveal small-scale particle dynamics in the eastern tropical North Pacific through Po-210/Pb-210 disequilibrium. Results showed significant deficiency of total Po-210 in oligotrophic seas and fractionation between dissolved and particulate Po-210 and Pb-210 in the scavenging process.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Craig L. McNeil, Eric A. D'Asaro, Mark A. Altabet, Roberta C. Hamme, Emilio Garcia-Robledo
Summary: Oxygen Deficient Zones (ODZs) in the oceans are receiving increased attention due to their importance in ocean nutrient cycling and their susceptibility to global warming. Conventional methods to study ODZs are costly and labor-intensive, but a Gas Tension Device (GTD) has been developed to measure ODZ denitrification more efficiently. The GTD measures dissolved gas pressure to calculate dissolved N2 concentration and has been successfully deployed in the Eastern Tropical North Pacific (ETNP).
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Timur Cinay, Diana Dumit, Ryan J. Woosley, Elisabeth L. Boles, Jarek Kwiecinski, Susan Mullen, Tyler J. Tamasi, Martin J. Wolf, Colette L. Kelly, Nicole M. Travis, Karen L. Casciotti, Andrew R. Babbin
Summary: This study constrained the relative contribution of biogeochemical processes to observable features in the Eastern Tropical North Pacific. It revealed new chemical features previously unobserved in the region and identified a tertiary nitrite maximum in addition to the primary and secondary nitrite maxima.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Multidisciplinary Sciences
Dan Fu, Ping Chang, Christina M. Patricola, R. Saravanan, Xue Liu, Hylke E. Beck
Summary: The Central American mountains play a role in reducing tropical cyclone activity in the eastern North Pacific by interrupting moisture transport from the Caribbean Sea on a seasonal timescale, reducing TC activity by up to 35%.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Jose Martin Pujolar, Mozes P. K. Blom, Andrew Hart Reeve, Jonathan D. Kennedy, Petter Zahl Marki, Thorfinn S. Korneliussen, Benjamin G. Freeman, Katerina Sam, Ethan Linck, Tri Haryoko, Bulisa Iova, Bonny Koane, Gibson Maiah, Luda Paul, Martin Irestedt, Knud Andreas Jonsson
Summary: Using genomic data and demographic models, the authors show that populations in high elevations become isolated, while montane populations maintain gene flow for further colonization. Tropical mountains are important for Earth's biodiversity, with montane species typically inhabiting multiple mountainous regions. Pleistocene climate oscillations have had a significant impact on species demographics.
NATURE COMMUNICATIONS
(2022)
Article
Limnology
Megan E. Duffy, Jacquelyn A. Neibauer, Jamee Adams, Rachel A. Lundeen, Gabrielle Rocap, Anitra E. Ingalls, Clara A. Fuchsman, Richard G. Keil
Summary: This study identified peptides in suspended and sinking particles from the oxygen-deficient zone in the eastern tropical North Pacific and in a culture of the cyanobacterium Prochlorococcus using a de novo-discovery approach. The results show that de novo peptides are taxonomically specific and can enhance database-driven methods. The analysis of the particles also revealed the presence of fungal proteins in deep sinking particles, suggesting the important role of fungi in marine organic matter cycling. Additionally, observations were made on the post-translationally modified cyanobacterial peptides in the sediment trap sample, indicating the association between cellular location and early preservation in the detrital pool. The presence of modified amino acids in sinking and suspended particles suggests that extracellular protein degradation contributes to the pools of refractory organic nitrogen.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Review
Limnology
Angelicque E. White, Julie Granger, Corday Selden, Mary R. Gradoville, Lindsey Potts, Annie Bourbonnais, Robinson W. Fulweiler, Angela N. Knapp, Wiebke Mohr, Pia H. Moisander, Craig R. Tobias, Mathieu Caffin, Samuel T. Wilson, Mar Benavides, Sophie Bonnet, Margaret R. Mulholland, Bonnie X. Chang
LIMNOLOGY AND OCEANOGRAPHY-METHODS
(2020)
Article
Environmental Sciences
Alyson E. Santoro, Carolyn Buchwald, Angela N. Knapp, William M. Berelson, Douglas G. Capone, Karen L. Casciotti
Summary: Marine oxygen deficient zones are dynamic areas of microbial nitrogen cycling, with nitrification playing a key role. Depth-integrated inventories of ammonium and nitrite were positively correlated with depth-integrated primary production, while ammonia oxidation rates were undetectable in trap-collected sinking particulate material. N2O concentrations in the upper oxycline reached values of >140 nM, supporting potentially higher air-sea fluxes of N2O in the offshore Eastern Tropical South Pacific than previously estimated.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Marine & Freshwater Biology
Karen E. Selph, Rasmus Swalethorp, Michael R. Stukel, Thomas B. Kelly, Angela N. Knapp, Kelsey Fleming, Tabitha Hernandez, Michael R. Landry
Summary: The research investigated the biomass and composition of phytoplankton community in the deep-water Gulf of Mexico in May 2017 and May 2018. The phytoplankton in the Gulf of Mexico had a chlorophyll a concentration of about 10 mg/m2 and autotrophic carbon ranging from 463 to 1268 mg/m2, with dominance by picoplankton. The taxonomic composition of phytoplankton varied between the mixed layer and deep chlorophyll maximum, reflecting different pathways for primary production.
JOURNAL OF PLANKTON RESEARCH
(2022)
Article
Marine & Freshwater Biology
Natalia Yingling, Thomas B. Kelly, Taylor A. Shropshire, Michael R. Landry, Karen E. Selph, Angela N. Knapp, Sven A. Kranz, Michael R. Stukel
Summary: The study reveals that nitrogen and light co-limit the growth of different phytoplankton taxa in the ocean. Observations from the deep-water Gulf of Mexico show a decline in primary productivity with depth, strong diel patterns in nitrate uptake, and no diel variability in ammonium uptake.
JOURNAL OF PLANKTON RESEARCH
(2022)
Article
Marine & Freshwater Biology
Angela N. Knapp, Rachel K. Thomas, Michael R. Stukel, Thomas B. Kelly, Michael R. Landry, Karen E. Selph, Estrella Malca, Trika Gerard, John Lamkin
Summary: This study used geochemical tools to analyze the sources and importance of nitrogen in supporting export production in the oligotrophic Gulf of Mexico. The results indicate that the majority of export production is supported by subsurface nitrate, and the contribution of N-2 fixation is relatively small.
JOURNAL OF PLANKTON RESEARCH
(2022)
Article
Multidisciplinary Sciences
Thomas B. Kelly, Angela N. Knapp, Michael R. Landry, Karen E. Selph, Taylor A. Shropshire, Rachel K. Thomas, Michael R. Stukel
Summary: The open-ocean Gulf of Mexico has highly stratified and oligotrophic surface waters, but anomalous high nitrogen export rates are supported by lateral advection of organic matter.
NATURE COMMUNICATIONS
(2021)
Article
Oceanography
James L. Pinckney, Sarah Zaunbrecher, Susan Lang, Alicia Wilson, Angela Knapp
Summary: Benthic microalgae in the surface sediments of shallow continental shelves exhibit seasonal variations in abundance, which are positively correlated with bottom water temperature. BMA biomass exceeds phytoplankton and is primarily composed of diatoms, with cyanobacteria and green microalgae as minor components.
CONTINENTAL SHELF RESEARCH
(2022)
Article
Marine & Freshwater Biology
Trika Gerard, John T. Lamkin, Thomas B. Kelly, Angela N. Knapp, Raul Laiz-Carrion, Estrella Malca, Karen E. Selph, Akihiro Shiroza, Taylor A. Shropshire, Michael R. Stukel, Rasmus Swalethorp, Natalia Yingling, Michael R. Landry
Summary: This study investigated the migration process of western Atlantic bluefin tuna (ABT) from their feeding grounds to the Gulf of Mexico for spawning, and explored the nutrient sources and food-web structure of their preferred habitat. The results showed that lateral transport from the continental slope region may play a more significant role in determining the available habitat for larvae than eddy edges.
JOURNAL OF PLANKTON RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Zhou Liang, Robert T. Letscher, Angela N. Knapp
Summary: DOP plays a crucial role in the surface ocean, influencing global primary production and nitrogen fixation. The distribution of DOP concentrations is controlled by phosphate and iron stress in marine environments.
Article
Environmental Sciences
Kristina A. Confesor, Corday R. Selden, Kimberly E. Powell, Laura A. Donahue, Travis Mellett, Salvatore Caprara, Angela N. Knapp, Kristen N. Buck, P. Dreux Chappell
Summary: This study investigated the presence and environmental preferences of Trichodesmium clades in the waters of the West Florida Shelf. The results showed that T. erythraeum was mainly found in shallow waters, while T. thiebautii preferred deeper waters and was affected by iron limitation.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Robert T. Letscher, Wei-Lei Wang, Zhou Liang, Angela N. Knapp
Summary: Marine dissolved organic phosphorus (DOP) plays an important role as a nutrient for marine autotrophs and contributes to the annual net community production (ANCP). This study used a global dataset of marine DOP to investigate the regional variability of DOP utilization by autotrophs contributing to ANCP. The results show that approximately 25% of ANCP is accumulated as DOP, with regional variations ranging from 8% to 50% across different biomes. Shallow export and remineralization of DOP in the subtropical regions contribute to the regeneration of phosphate within the upper thermocline, and the transport of DOP from net production regions to net consumption regions is facilitated by subtropical gyres.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Multidisciplinary Sciences
Zhou Liang, Kelly McCabe, Sarah E. E. Fawcett, Heather J. J. Forrer, Fuminori Hashihama, Catherine Jeandel, Dario Marconi, Helene Planquette, Mak A. A. Saito, Jill A. A. Sohm, Rachel K. K. Thomas, Robert T. T. Letscher, Angela N. N. Knapp
Summary: The concentration distribution of dissolved organic phosphorus (DOP) in the global surface ocean is crucial for understanding marine biogeochemical processes. This study presents a comprehensive database of marine DOP concentration measurements, which provides valuable insights into the spatial distributions of DOP and is especially useful for researchers studying marine primary production and nitrogen fixation.
Article
Limnology
Carlos Miranda, Rene M. M. Boiteau, Amy M. M. McKenna, Angela N. N. Knapp
Summary: Marine dissolved organic carbon and nitrogen (DOC and DON) are important global carbon and nutrient reservoirs. An optimized analytical strategy was developed to recover marine DON for molecular characterization. Different solid phase extraction (SPE) sorbents showed varying retention efficiencies for DON, with C-18 recovering the highest amount (95%) compared to PPL (23%). The molecular composition of DON extracts differed between sorbents, with optimized methods capturing low molecular weight peptide-like compounds.
LIMNOLOGY AND OCEANOGRAPHY-METHODS
(2023)
Article
Multidisciplinary Sciences
Sophie Bonnet, Cecile Guieu, Vincent Taillandier, Cedric Boulart, Pascale Bouruet-Aubertot, Frederic Gazeau, Carla Scalabrin, Matthieu Bressac, Angela N. Knapp, Yannis Cuypers, David Gonzalez-Santana, Heather J. Forrer, Jean-Michel Grisoni, Olivier Grosso, Jeremie Habasque, Mercedes Jardin-Camps, Nathalie Leblond, Frederic A. C. Le Moigne, Anne Lebourges-Dhaussy, Caroline Lory, Sandra Nunige, Elvira Pulido-Villena, Andrea L. Rizzo, Geraldine Sarthou, Chloe Tilliette
Summary: Iron is a vital nutrient for ocean productivity, and this study reveals the previously unknown mechanism of natural iron fertilization in the ocean. Shallow hydrothermal fluids along the Tonga volcanic arc significantly impact iron concentrations in the photic layer, stimulating biological activity and resulting in extensive chlorophyll blooms. This iron enrichment leads to higher diazotroph activity and carbon export fluxes, providing a regional hotspot sink for atmospheric CO2.
Article
Geosciences, Multidisciplinary
Zhibo Shao, Yangchun Xu, Hua Wang, Weicheng Luo, Lice Wang, Yuhong Huang, Nona Sheila R. Agawin, Ayaz Ahmed, Mar Benavides, Mikkel Bentzon-Tilia, Ilana Berman-Frank, Hugo Berthelot, Isabelle C. Biegala, Mariana B. Bif, Antonio Bode, Sophie Bonnet, Deborah A. Bronk, Mark V. Brown, Lisa Campbell, Douglas G. Capone, Edward J. Carpenter, Nicolas Cassar, Bonnie X. Chang, Dreux Chappell, Yuh-ling Lee Chen, Matthew J. Church, Francisco M. Cornejo-Castillo, Amalia Maria Sacilotto Detoni, Scott C. Doney, Cecile Dupouy, Marta Estrada, Camila Fernandez, Bieito Fernandez-Castro, Debany Fonseca-Batista, Rachel A. Foster, Ken Furuya, Nicole Garcia, Kanji Goto, Jesus Gago, Mary R. Gradoville, M. Robert Hamersley, Britt A. Henke, Cora Horstmann, Amal Jayakumar, Zhibing Jiang, Shuh-Ji Kao, David M. Karl, Leila R. Kittu, Angela N. Knapp, Sanjeev Kumar, Julie LaRoche, Hongbin Liu, Jiaxing Liu, Caroline Lory, Carolin R. Loscher, Emilio Maranon, Lauren F. Messer, Matthew M. Mills, Wiebke Mohr, Pia H. Moisander, Claire Mahaffey, Robert Moore, Beatriz Mourino-Carballido, Margaret R. Mulholland, Shin-ichiro Nakaoka, Joseph A. Needoba, Eric J. Raes, Eyal Rahav, Teodoro Ramirez-Cardenas, Christian Furbo Reeder, Lasse Riemann, Virginie Riou, Julie C. Robidart, Vedula V. S. S. Sarma, Takuya Sato, Himanshu Saxena, Corday Selden, Justin R. Seymour, Dalin Shi, Takuhei Shiozaki, Arvind Singh, Rachel E. Sipler, Jun Sun, Koji Suzuki, Kazutaka Takahashi, Yehui Tan, Weiyi Tang, Jean-Eric Tremblay, Kendra Turk-Kubo, Zuozhu Wen, Angelicque E. White, Samuel T. Wilson, Takashi Yoshida, Jonathan P. Zehr, Run Zhang, Yao Zhang, Ya-Wei Luo
Summary: This study presents an updated version (version 2) of the global oceanic diazotroph database, which significantly increases the number of in situ diazotrophic measurements and provides more detailed insights into nitrogen fixation in the global ocean. Version 2 yields significantly higher estimates of nitrogen fixation rates compared to version 1, particularly in the South Pacific and North Atlantic regions. Furthermore, additional data sheets for non-cyanobacterial diazotrophs and cell-specific N2 fixation rates have been included in version 2, enhancing the database's comprehensiveness.
EARTH SYSTEM SCIENCE DATA
(2023)