More Like this

1. Re‐Evaluating Hydrogen Sulfide as a Sink for Cadmium and Zinc in the Oxic to Suboxic Upper Water Column of the Pacific Ocean

   https://doi.org/10.1029/2023GB007881  

   Buckley, N R; Black, E E; Kenyon, J A; Lanning, N T; Sieber, M; Conway, T M; Fitzsimmons, J N; Cutter, G A (March 2024, Global Biogeochemical Cycles)

   Abstract Hydrogen sulfide is produced by heterotrophic bacteria in anoxic waters and via carbonyl sulfide hydrolysis and phytoplankton emissions under oxic conditions. Apparent losses of dissolved cadmium (dCd) and zinc (dZn) in oxygen minimum zones (OMZs) of the Atlantic and Pacific Oceans have been attributed to metal‐sulfide precipitation formed via dissimilatory sulfate reduction. It has also been argued that such a removal process could be a globally important sink for dCd and dZn. However, our studies from the North Pacific OMZ show that dissolved and particulate sulfide concentrations are insufficient to support the removal of dCd via precipitation. In contrast, apparent dCd and dZn deficits in the eastern tropical South Pacific OMZ do reside in the oxycline with particulate sulfide maxima, but they also coincide with the secondary fluorescence maxima, suggesting that removal via sulfide precipitation may be due to a combination of dissimilatory and assimilatory sulfate reduction. Notably, dCd loss via precipitation with sulfide from assimilatory reduction was found in upper oxic waters of the North Pacific. While dissimilatory sulfate reduction may explain local dCd and dZn losses in some OMZs, our evaluation of North Pacific OMZs demonstrates that dCd and dZn losses are unlikely to be a globally relevant sink. Nevertheless, metal sulfide losses due to assimilatory sulfate reduction in surface waters should be considered in future biogeochemical models of oceanic Cd (and perhaps Zn) cycling. 

   more » « less
2. Ocean deoxygenation and zooplankton: Very small oxygen differences matter

   https://doi.org/10.1126/sciadv.aau5180  

   Wishner, K. F.; Seibel, B. A.; Roman, C.; Deutsch, C.; Outram, D.; Shaw, C. T.; Birk, M. A.; Mislan, K. A.; Adams, T. J.; Moore, D.; et al (December 2018, Science Advances)

   Oxygen minimum zones (OMZs), large midwater regions of very low oxygen, are expected to expand as a result of climate change. While oxygen is known to be important in structuring midwater ecosystems, a precise and mechanistic understanding of the effects of oxygen on zooplankton is lacking. Zooplankton are important components of midwater food webs and biogeochemical cycles. Here, we show that, in the eastern tropical North Pacific OMZ, previously undescribed submesoscale oxygen variability has a direct effect on the distribution of many major zooplankton groups. Despite extraordinary hypoxia tolerance, many zooplankton live near their physiological limits and respond to slight (≤1%) changes in oxygen. Ocean oxygen loss (deoxygenation) may, thus, elicit major unanticipated changes to midwater ecosystem structure and function. 

   more » « less
3. Ocean deoxygenation and zooplankton: Very small oxygen differences matter

   https://doi.org/DOI: 10.1126/sciadv.aau5180  

   Wishner, K.F.; Seibel, B.A.; Roman, C.; Deutsch, C.; Outram, D.; Shaw, C.T.; Birk, M.A.; Mislan, K.A.S.; Adams, T.J.; Moore, D.; et al (December 2018, Science advances)

   Oxygen minimum zones (OMZs), large midwater regions of very low oxygen, are expected to expand as a result of climate change. While oxygen is known to be important in structuring midwater ecosystems, a precise and mechanistic understanding of the effects of oxygen on zooplankton is lacking. Zooplankton are important components of midwater food webs and biogeochemical cycles. Here, we show that, in the eastern tropical North Pacific OMZ, previously undescribed submesoscale oxygen variability has a direct effect on the distribution of many major zooplankton groups. Despite extraordinary hypoxia tolerance, many zooplankton live near their physiological limits and respond to slight (≤1%) changes in oxygen. Ocean oxygen loss (deoxygenation) may, thus, elicit major unanticipated changes to midwater ecosystem structure and function. 

   more » « less
4. Vertical distribution of planktic foraminifera through an oxygen minimum zone: how assemblages and test morphology reflect oxygen concentrations

   https://doi.org/10.5194/bg-2020-280  

   Davis, C.V.; Wishner, K.; Renema, W.; Hull, P.M. (January 2021, Biogeosciences)

   null (Ed.)

   Abstract. Oxygen-depleted regions of the global ocean are rapidly expanding, with important implications for global biogeochemical cycles. However, our ability to make projections about the future of oxygen in the ocean is limited by a lack of empirical data with which to test and constrain the behavior of global climatic and oceanographic models. We use depth-stratified plankton tows to demonstrate that some species of planktic foraminifera are adapted to life in the heart of the pelagic oxygen minimum zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the eastern tropical North Pacific OMZ. The tests of the former are preserved in marine sediments and could be used to trace the extent and intensity of low-oxygen pelagic habitats in the fossil record. Additional morphometric analyses of G. hexagonus show that tests found in the lowest oxygen environments are larger, more porous, less dense, and have more chambers in the final whorl. The association of this species with the OMZ and the apparent plasticity of its test in response to ambient oxygenation invites the use of G. hexagonus tests in sediment cores as potential proxies for both the presence and intensity of overlying OMZs. 

   more » « less
5. Assessment of Tropical Cyclone Activity From a Statistical‐Dynamical Downscaling Model in the Northern Pacific and Atlantic Oceans

   https://doi.org/10.1029/2025JD043947  

   Han, Shuting; Lee, Chia‐Ying; Camargo, Suzana J; Wang, Shuguang (October 2025, Journal of Geophysical Research: Atmospheres)

   Abstract This study investigates the interannual variability of tropical cyclones (TCs) from 1951 to 2019 using observational data sets and synthetic TCs generated by the Columbia HAZard (CHAZ) model, a hybrid TC risk model. Analysis of TC genesis and landfall indicates that CHAZ reasonably captures the spatial distribution of TC activity during the Northern Hemisphere TC season in the tropical western Pacific, eastern Pacific, and Atlantic Ocean basins. The CHAZ simulation of TC genesis, track distribution, and landfall latitude is most accurate in the North Atlantic, where interannual variability is also best represented. Observed interannual correlation coefficients between TC genesis and landfall generally exceed 0.5 in the western Pacific and North Atlantic, but are lower in the eastern Pacific; CHAZ simulates higher correlations across all three basins than observations. Further analysis examines the influence of seven climate modes: El Niño‐Southern Oscillation, Pacific Meridional Mode (PMM), Atlantic Meridional Mode (AMM), Tropical Upper‐Tropospheric Trough in the Pacific (TUTT_Pac) and Atlantic (TUTT_Atl), Western Pacific Subtropical High, and North Atlantic Subtropical High. In the western and eastern North Pacific Ocean basins, heightened TC activity is observed during positive PMM and negative TUTT_Pac phases. In the Atlantic, La Niña, positive AMM, and negative TUTT_Atl phases enhance TC activity. Interactions between modes can amplify or dampen their individual effects; notably, the combination of negative TUTT_Atl and positive AMM phases increases TC landfall occurrence in the Atlantic by over 50% relative to climatological norms in both observations and CHAZ. 

   more » « less