268 research outputs found

    Fisheries aspects of seamounts and Taylor columns

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    Three hypotheses to explain the high biological productivity observed over the southern Emperor-northern Hawaiian Ridge seamounts are suggested: larval retention to hydrodynamic trapping in a Taylor column, nutrient enrichment by topographically-induced upwelling , and attraction of organisms to stationary physical substrates. Quasi-geostrophic wave-topography interactions are considered, with particular regard to Taylor column dynamics. Data from three hydrographic surveys over Southeast Hancock Seamount conducted during summer 1984 and winter 1985 are examined for evidence supporting these hypotheses. The two summer surveys show features consistent with a two-layer systems having bottom-intensified anticyclonic flow around the seamount, in agreement with stratified Taylor column theory. The winter survey indicates more homogeneous anticyclonic flow around the seamount, suggesting the existence of a barotropic Taylor column. Possibly intense internal wave motion and upwelling are suggested by strong, localized vertical southern deflections in across-seamount sections taken during the summer surveys. These deflections are reminiscent of wave-topography interactions is atmosphere flow over terrestrial mountains. The second summer survey showed possible upwelling I the lee of the topographically-forced divergence.http://archive.org/details/fisheriesaspects00braiLieutenant, Junior grade, NOAA CorpsApproved for public release; distribution is unlimited

    “Sounding” Like Lake-Effect Snow: Evaluating the Thermodynamic and Synoptic Setup of Northwest Indiana Lake-Effect Events Using Local Profiles and Numerical Modeling

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    Lake-effect snow presents significant hazards for Northwest Indiana, which necessitates the need for accurate forecasts for these events. Recent radiosonde observations were taken routinely with radiosonde launches by Valparaiso University’s Aviation Team surrounding lake-effect events. From these soundings, thermodynamic environments are analyzed in conjunction with numerical simulations and official Green Bay soundings of 12 lake-effect precipitation events. This study will use the data from the sounding profiles and from numerical simulations to determine similarities and differences within the thermodynamic and synoptic environments surrounding these events. Through analysis of these pre-storm local environments, unique thresholds will be identified in environmental parameters associated with the setup and formation of lake-effect events over the southern Lake Michigan region. Creating a mean sounding for Northwest Indiana of these lake-effect setups would be optimal for aiding forecasts of similar future events. This analysis should allow observation of model biases and enhance the ability to predict lake-effect snow

    Ecological Impacts of the 2015/16 El Niño in the Central Equatorial Pacific

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    The authors thank Cisco Werner (NOAA/NMFS) for proposing this special issue and encouraging our submission. We thank each of the editors, Stephanie Herring, Peter Stott, and Nikos Christidis, for helpful guidance and support throughout the submittal process. We also thank each of the anonymous external reviewers for thoughtful guidance and suggestions to improve the manuscript. REB, TO, RV, AH, and BVA are grateful for support from the NOAA Coral Reef Conservation Program. AC acknowledges support from the National Science Foundation for the following awards: OCE 1537338, OCE 1605365, and OCE 1031971. This is PMEL contribution no. 4698. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government. The views expressed in the article are not necessarily those of the U.S. government. (NOAA Coral Reef Conservation Program; OCE 1537338 - National Science Foundation; OCE 1605365 - National Science Foundation; OCE 1031971 - National Science Foundation

    Ocean acidification has impacted coral growth on the great barrier reef

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    Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 47(19), (2020): e2019GL086761, doi:10.1029/2019GL086761.Ocean acidification (OA) reduces the concentration of seawater carbonate ions that stony corals need to produce their calcium carbonate skeletons and is considered a significant threat to the functional integrity of coral reef ecosystems. However, detection and attribution of OA impact on corals in nature are confounded by concurrent environmental changes, including ocean warming. Here we use a numerical model to isolate the effects of OA and temperature and show that OA alone has caused 13 ± 3% decline in the skeletal density of massive Porites corals on the Great Barrier Reef since 1950. This OA‐induced thinning of coral skeletons, also evident in Porites from the South China Sea but not in the central Pacific, reflects enhanced acidification of reef water relative to the surrounding open ocean. Our finding reinforces concerns that even corals that might survive multiple heatwaves are structurally weakened and increasingly vulnerable to the compounding effects of climate change.This work was supported in part by the U.S. National Science Foundation (OCE‐1737311), the Robertson Foundation, the Tiffany & Co. Foundation, the Atlantic Donor Advised Fund, the Investment in Science Fund and The Andrew W. Mellon Foundation Endowed Fund for Innovative Research at the Woods Hole Oceanographic Institution. The data generated in this study are included in the Supporting Information (Data Sets S1–S3) and are also being archived at NOAA National Centers for Environmental Information (NCEI)‐Paleoclimatology Data repository.2021-02-2

    Coral macrobioerosion is accelerated by ocean acidification and nutrients

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    Author Posting. © The Author(s), 2014]. This is the author's version of the work. It is posted here by permission of Geological Society of America for personal use, not for redistribution. The definitive version was published in Geology 43 (2015): 7-10, doi: 10.1130/G36147.1.Coral reefs exist in a delicate balance between calcium carbonate (CaCO3) production and CaCO3 loss. Ocean acidification (OA), the CO2-driven decline in seawater pH and CaCO3 saturation state (℩), threatens to tip this balance by decreasing calcification, and increasing erosion and dissolution. While multiple CO2 manipulation experiments show coral calcification declines under OA, the sensitivity of bioerosion to OA is less well understood. Previous work suggests that coral and coral reef bioerosion increase with decreasing seawater ℩. However, in the surface ocean, ℩ and nutrient concentrations often covary, making their relative influence difficult to resolve. Here, we exploit unique natural gradients in ℩ and nutrients across the Pacific basin to quantify the impact of these factors, together and independently, on macrobioerosion rates of coral skeletons. Using an automated program to quantify macrobioerosion in 3-D computerized tomography (CT) scans of coral cores, we show that macrobioerosion rates of live Porites colonies in both low-nutrient (oligotrophic) and high-nutrient (>1 ”M nitrate) waters increase significantly as ℩ decreases. However, the sensitivity of macrobioerosion to ℩ is ten times greater under high-nutrient conditions. Our results demonstrate that OA (decreased ℩) alone can increase coral macrobioerosion rates, but the interaction of OA with local stressors exacerbates its impact, accelerating a shift toward net CaCO3 removal from coral reefs.This work was supported by NSF OCE 1041106 to A.L.C. and K.E.S., NSF OCE 1220529 to A.L.C., TNC award PNA/WHOI061810 to A.L.C., NSF Graduate Research Fellowships to T.M.D. and H.C.B., and a WHOI-OLI post-doctoral fellowship to K.E.S.2015-11-1

    The Iowa Homemaker vol.22, no.8

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    Keeping Up With Today, Virginia Brainard, page 4 Letter from Overseas, Martha Kitchen, page 5 Nutrition in the Nursery, Phyllis Lee, page 6 Iowa Staters Feed Wartime Washington, Eileen Dudgeon, page 7 What’s New in Home Economics, Helen Horton, page 8 We Britons Tighten Our Belts, Mr. and Mrs. Sharp, page 10 In a Teacher’s World, Betty Roth, page 11 Across Alumnae Desks, Mary Ellen Sullivan, page 12 Alums in the News, Janet Russell, page 14 We Recommend, Eileen Dudgeon, page 15 Textiles See Action, Ann Mason, page 1

    The rarity of depth refugia from coral bleaching heat stress in the Western and Central Pacific Islands

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    Some researchers have suggested that corals living in deeper reefs may escape heat stress experienced by shallow corals. We evaluated the potential of deep coral reef refugia from bleaching stress by leveraging a long record of satellite-derived sea surface temperature data with a temporal, spatial, and depth precision of in situ temperature records. We calculated an in situ stress metric using a depth bias-adjusted threshold for 457 coral reef sites among 49 islands in the western and central Pacific Ocean over the period 2001–2017. Analysis of 1,453 heating events found no meaningful depth refuge from heat stress down to 38 m, and no significant association between depth and subsurface heat stress. Further, the surface metric underestimated subsurface stress by an average of 39.3%, across all depths. Combining satellite and in situ temperature data can provide bleaching-relevant heat stress results to avoid misrepresentation of heat stress exposure at shallow reefs

    Case report: tracking data from foraging hawksbill turtles in the northern Red Sea

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    Background: Hawksbill turtles (Eretmochelys imbricata) are Critically Endangered throughout their global range, and concerningly little is known about this species in the Red Sea. With large-scale coastal development projects underway in the northern Red Sea, it is critical to understand the movement and habitat use patterns of hawksbill turtles in this environmentally unique region, so that effective conservation strategies can be implemented. We satellite tagged three hawksbill turtles, one 63 cm curved carapace length adult male captured near Wahlei Island, one 55 cm turtle captured in the Gulf of Aqaba, and one 56 cm turtle suffering from a floating syndrome which was captured at Waqqadi Island, rehabilitated, and released at Waqqadi Island. Turtles were tracked for 156, 199, and 372 days between October 2020 and November 2021. Results: We calculated the home ranges and core use areas of hawksbill turtles using kernel-density estimations and found that each turtle showed high fidelity to their foraging sites. Home ranges calculated with GPS-derived locations ranged between 13.6 and 2.86 km2, whereas home ranges calculated with Argos-derived locations ranged from 38.98 to 286.45 km2. GPS-derived locations also revealed a higher proportion of time spent in coral and rock habitats compared to Argos, based on location overlap with the Allen Coral Reef Atlas. We also found that turtles were making shallow dives, usually remaining between 0 and 5 m. Conclusions: While the number of tracked turtles in this study was small, it represents an important contribution to the current understanding of spatial ecology among foraging hawksbill turtles globally, and provides the first-ever reported hawksbill turtle tracking data from the Red Sea. Our results suggest that protecting coral reef habitats and implementing boating speed limits near reefs could be effective conservation measures for foraging hawksbill turtles in the face of rapid coastal development

    Heterotrophy of oceanic particulate organic matter elevates net ecosystem calcification

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    Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(16), (2019): 9851-9860, doi:10.1029/2019GL083726.Coral reef calcification is expected to decline due to climate change stressors such as ocean acidification and warming. Projections of future coral reef health are based on our understanding of the environmental drivers that affect calcification and dissolution. One such driver that may impact coral reef health is heterotrophy of oceanic‐sourced particulate organic matter, but its link to calcification has not been directly investigated in the field. In this study, we estimated net ecosystem calcification and oceanic particulate organic carbon (POCoc) uptake across the Kāne'ohe Bay barrier reef in Hawai'i. We show that higher rates of POCoc uptake correspond to greater net ecosystem calcification rates, even under low aragonite saturation states (Ωar). Hence, reductions in offshore productivity may negatively impact coral reefs by decreasing the food supply required to sustain calcification. Alternatively, coral reefs that receive ample inputs of POCoc may maintain higher calcification rates, despite a global decline in Ωar.Data needed for calculations are available in the supporting information. Additional data can be provided upon request directly from the corresponding author or accessed by links provided in the supporting information. The authors declare no competing financial interests. We thank Texas Sea Grant for providing partial funding for this project to A. Kealoha through the Grants‐In‐Aid of Graduate Research Program. We also thank the NOAA Nancy Foster Scholarship for PhD program funding to A. Kealoha and Texas A&M University for funds awarded to Shamberger that supported this work. This research was also supported by funding from National Science Foundation Grant OCE‐1538628 to RappĂ©. The Hawaii Institute of Marine Biology (particularly the RappĂ© Lab and Jason Jones), NOAA's Coral Reef Ecosystem Program, Connie Previti, Serena Smith, and Chris Maupin were instrumental in sample collection and data analysis.2020-02-2
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