1
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Stukel MR, Gerard T, Kelly TB, Knapp AN, Laiz-Carrión R, Lamkin JT, Landry MR, Malca E, Selph KE, Shiroza A, Shropshire TA, Swalethorp R. Plankton food webs in the oligotrophic Gulf of Mexico spawning grounds of Atlantic bluefin tuna. JOURNAL OF PLANKTON RESEARCH 2022; 44:763-781. [PMID: 36045950 PMCID: PMC9424712 DOI: 10.1093/plankt/fbab023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/08/2021] [Accepted: 03/17/2021] [Indexed: 06/15/2023]
Abstract
We used linear inverse ecosystem modeling techniques to assimilate data from extensive Lagrangian field experiments into a mass-balance constrained food web for the Gulf of Mexico open-ocean ecosystem. This region is highly oligotrophic, yet Atlantic bluefin tuna (ABT) travel long distances from feeding grounds in the North Atlantic to spawn there. Our results show extensive nutrient regeneration fueling primary productivity (mostly by cyanobacteria and other picophytoplankton) in the upper euphotic zone. The food web is dominated by the microbial loop (>70% of net primary productivity is respired by heterotrophic bacteria and protists that feed on them). By contrast, herbivorous food web pathways from phytoplankton to metazoan zooplankton process <10% of the net primary production in the mixed layer. Nevertheless, ABT larvae feed preferentially on podonid cladocerans and other suspension-feeding zooplankton, which in turn derive much of their nutrition from nano- and micro-phytoplankton (mixotrophic flagellates, and to a lesser extent, diatoms). This allows ABT larvae to maintain a comparatively low trophic level (~4.2 for preflexion and postflexion larvae), which increases trophic transfer from phytoplankton to larval fish.
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Affiliation(s)
| | - Trika Gerard
- Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA), Miami, FL 33149, USA
| | - Thomas B Kelly
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Angela N Knapp
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Raúl Laiz-Carrión
- Centro Oceanográfico De Malaga, Instituto Español Del Oceanografía, Fuengirola, Spain
| | - John T Lamkin
- Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration (NOAA), Miami, FL 33149, USA
| | - Michael R Landry
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - Estrella Malca
- Cooperative Institute For Marine and Atmospheric Studies, University Of Miami, Miami, FL 33149, USA
| | - Karen E Selph
- Department of Oceanography, University of Hawaii At Manoa, Honolulu, HI 96822, USA
| | - Akihiro Shiroza
- Cooperative Institute For Marine and Atmospheric Studies, University Of Miami, Miami, FL 33149, USA
| | - Taylor A Shropshire
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
- Center for Ocean-Atmospheric Prediction Studies, Florida State University, Tallahassee, FL 32306, USA
| | - Rasmus Swalethorp
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
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2
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Busquets-Vass G, Newsome SD, Pardo MA, Calambokidis J, Aguíñiga-García S, Páez-Rosas D, Gómez-Gutiérrez J, Enríquez-Paredes LM, Gendron D. Isotope-based inferences of the seasonal foraging and migratory strategies of blue whales in the eastern Pacific Ocean. MARINE ENVIRONMENTAL RESEARCH 2021; 163:105201. [PMID: 33162117 DOI: 10.1016/j.marenvres.2020.105201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 10/15/2020] [Accepted: 10/24/2020] [Indexed: 06/11/2023]
Abstract
Migratory marine megafauna generally move vast distances between productive foraging grounds and environmentally stable breeding grounds, but characterizing how they use these habitats to maintain homeostasis and reproduce is difficult. We used isotope analysis of blue whale skin strata (n = 621) and potential prey (n = 300) to examine their migratory and foraging strategies in the eastern Pacific Ocean. Our results suggest that most whales in the northeast Pacific use a mixed income and capital breeding strategy, and use the California Current Ecosystem as their primary summer-fall foraging ground. A subset of individuals exhibited migratory plasticity and spend most of the year in the Gulf of California or Costa Rica Dome, two regions believed to be their primary winter-spring breeding grounds. Isotope data also revealed that whales in the southern Eastern Tropical Pacific generally do not forage in the northeast Pacific, which suggests a north-south population structure with a boundary near the equator.
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Affiliation(s)
- Geraldine Busquets-Vass
- Centro de Investigación Científica y Educación Superior de Ensenada, Unidad La Paz, Laboratorio de Macroecología Marina, Baja California Sur, Mexico; University of New Mexico, Biology Department, Albuquerque, NM, USA
| | - Seth D Newsome
- University of New Mexico, Biology Department, Albuquerque, NM, USA
| | - Mario A Pardo
- Consejo Nacional de Ciencia y Tecnología - Centro de Investigación Científica y Educación Superior de Ensenada, Unidad La Paz, Laboratorio de Macroecología Marina, Baja California Sur, Mexico
| | | | - Sergio Aguíñiga-García
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | - Diego Páez-Rosas
- Universidad San Francisco de Quito, Galapagos Science Center, Av. Alsacio Northía, Isla San Cristóbal, Galápagos, Ecuador; Dirección del Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, Av. Perimetral, Isla San Cristóbal, Galápagos, Ecuador
| | - Jaime Gómez-Gutiérrez
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | - Luis M Enríquez-Paredes
- Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Baja California, Mexico
| | - Diane Gendron
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico.
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3
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Baines SB, Chen X, Vogt S, Fisher NS, Twining BS, Landry MR. Microplankton trace element contents: implications for mineral limitation of mesozooplankton in an HNLC area. JOURNAL OF PLANKTON RESEARCH 2016; 38:256-270. [PMID: 27275029 PMCID: PMC4889991 DOI: 10.1093/plankt/fbv109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 11/19/2015] [Indexed: 05/25/2023]
Abstract
Mesozooplankton production in high-nutrient low-chlorophyll regions of the ocean may be reduced if the trace element concentrations in their food are insufficient to meet growth and metabolic demands. We used elemental microanalysis (SXRF) of single-celled plankton to determine their trace metal contents during a series of semi-Lagrangian drift studies in an HNLC upwelling region, the Costa Rica Dome (CRD). Cells from the surface mixed layer had lower Fe:S but higher Zn:S and Ni:S than those from the subsurface chlorophyll maximum at 22-30 m. Diatom Fe:S values were typically 3-fold higher than those in flagellated cells. The ratios of Zn:C in flagellates and diatoms were generally similar to each other, and to co-occurring mesozooplankton. Estimated Fe:C ratios in flagellates were lower than those in co-occurring mesozooplankton, sometimes by more than 3-fold. In contrast, Fe:C in diatoms was typically similar to that in zooplankton. RNA:DNA ratios in the CRD were low compared with other regions, and were related to total autotrophic biomass and weakly to the discrepancy between Zn:C in flagellated cells and mesozooplankton tissues. Mesozooplankton may have been affected by the trace element content of their food, even though trace metal limitation of phytoplankton was modest at best.
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Affiliation(s)
- Stephen B. Baines
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11789-5245, USA
| | - Xi Chen
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11789-5000, USA
| | - Stefan Vogt
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Nicholas S. Fisher
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11789-5000, USA
| | | | - Michael R. Landry
- Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0227, USA
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4
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Freibott A, Taylor AG, Selph KE, Liu H, Zhang W, Landry MR. Biomass and composition of protistan grazers and heterotrophic bacteria in the Costa Rica Dome during summer 2010. JOURNAL OF PLANKTON RESEARCH 2016; 38:230-243. [PMID: 27275027 PMCID: PMC4889989 DOI: 10.1093/plankt/fbv107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 11/19/2015] [Indexed: 05/10/2023]
Abstract
We investigated biomass and composition of heterotrophic microbes in the Costa Rica Dome during June-July 2010 as part of a broader study of plankton trophic dynamics. Because picophytoplankton (<2 μm) are known to dominate in this unique upwelling region, we hypothesized tight biomass relationships between size-determined predator-prey pairs (i.e. picoplankton-nano-grazers, nanoplankton-micro-grazers) within the microbial community. Integrated biomass of heterotrophic bacteria ranged from 180 to 487 mg C m-2 and was significantly correlated with total autotrophic carbon. Heterotrophic protist (H-protist) biomass ranged more narrowly from 488 to 545 mg C m-2, and was comprised of 60% dinoflagellates, 30% other flagellates and 11% ciliates. Nano-sized (<20 μm) protists accounted for the majority (57%) of grazer biomass and were positively correlated with picoplankton, partially supporting our hypothesis, but nanoplankton and micro-grazers (>20 μm) were not significantly correlated. The relative constancy of H-protist biomass among locations despite clear changes in integrated autotrophic biomass, Chl a, and primary production suggests that mesozooplankton may exert a tight top-down control on micro-grazers. Biomass-specific consumption rates of phytoplankton by protistan grazers suggest an instantaneous growth rate of 0.52 day-1 for H-protists, similar to the growth rate of phytoplankton and consistent with a trophically balanced ecosystem dominated by pico-nanoplankton interactions.
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Affiliation(s)
- Alexandra Freibott
- Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA, USA
- CORRESPONDING AUTHOR:
| | - Andrew G. Taylor
- Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA, USA
| | - Karen E. Selph
- Department of Oceanography, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Hongbin Liu
- The Hong Kong University of Science and Technology, Hong Kong Sar, China
| | - Wuchang Zhang
- Institute of Oceanography, Chinese Academy of Science, Qingdao, China
| | - Michael R. Landry
- Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA, USA
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5
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Jackson ML, Smith SL. Vertical distribution of Eucalanoid copepods within the Costa Rica Dome area of the Eastern Tropical Pacific. JOURNAL OF PLANKTON RESEARCH 2016; 38:305-316. [PMID: 27275032 PMCID: PMC4889992 DOI: 10.1093/plankt/fbv117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 12/07/2015] [Indexed: 05/25/2023]
Abstract
A variety of ecological strategies for tolerance of low-oxygen conditions within the Costa Rica Dome (CRD) area of the Eastern Tropical Pacific are documented for the copepod family Eucalanidae. During the summer of 2010, we compared the ecological strategies used by the Eucalanidae inside and outside the central CRD region. We compared the vertical and horizontal distributions of five species, Eucalanus inermis, Subeucalanus subtenuis, Subeucalanus subcrassus, Subeucalanus pileatus and Pareucalanus attenuatus together with Rhincalanus species, in the epipelagic (upper 200 m) among four locations, which we grouped into a section roughly crossing the core CRD area (inside-outside core CRD). The coastal area outside the CRD supported the most diverse assemblage, whereas overall abundance of Eucalanidae in the central CRD was 2-fold greater than outside and dominated by E. inermis (>60%). Eucalanidae in the central CRD had a shallow depth distribution, closely associated with the shallow thermocline (10-20 m). There was no evidence of daily vertical migration in the central CRD, but E. inermis demonstrated vertical migration outside the CRD. The vertical abundance patterns of Eucalanidae in the CRD region reflect complex interactions between subtle physical-chemical differences and food resources.
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Affiliation(s)
- Melanie L. Jackson
- University of Maryland Center for Environmental Science, Horn Point Laboratory, Cambridge, MD21613, USA
| | - Sharon L. Smith
- Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
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6
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Gutiérrez-Rodríguez A, Selph KE, Landry MR. Phytoplankton growth and microzooplankton grazing dynamics across vertical environmental gradients determined by transplant in situ dilution experiments. JOURNAL OF PLANKTON RESEARCH 2016; 38:271-289. [PMID: 27275030 PMCID: PMC4889981 DOI: 10.1093/plankt/fbv074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 08/09/2015] [Indexed: 05/25/2023]
Abstract
The Costa Rica Dome (CRD) represents a classic case of the bloom-forming capacity of small phytoplankton. Unlike other upwelling systems, autotrophic biomass in the CRD is dominated by picocyanobacteria and small eukaryotes that outcompete larger diatoms and reach extremely high biomass levels. We investigated responses of the subsurface phytoplankton community of the CRD to changes associated with vertical displacement of water masses, coupling in situ transplanted dilution experiments with flow cytometry and epifluorescence microscopy to assess group-specific dynamics. Growth rates of Synechococcus (SYN) and photosynthetic picoeukaryotes (PEUK) were positively correlated with light (Rpearson_SYN = 0.602 and Rpearson_PEUK = 0.588, P < 0.001). Growth rates of Prochlorococcus (PRO), likely affected by photoinhibition, were not light correlated (Rpearson_PRO = 0.101, P = 0.601). Overall, grazing and growth rates were closely coupled in all picophytoplankton groups (Rspearman_PRO = 0.572, Rspearman_SYN = 0.588, Rspearman_PEUK = 0.624), and net growth rates remained close to zero. Conversely, the abundance and biomass of larger phytoplankton, mainly diatoms, increased more than 10-fold in shallower transplant incubations indicating that, in addition to trace-metal chemistry, light also plays a significant role in controlling microphytoplankton populations in the CRD.
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Affiliation(s)
| | - Karen E Selph
- Department of Oceanography , University of Hawaii at Manoa , Honolulu, Hi 96822 , USA
| | - Michael R Landry
- Scripps Institution of Oceanography , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA
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7
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Krause JW, Stukel MR, Taylor AG, Taniguchi DAA, De Verneil A, Landry MR. Net biogenic silica production and the contribution of diatoms to new production and organic matter export in the Costa Rica Dome ecosystem. JOURNAL OF PLANKTON RESEARCH 2016; 38:216-229. [PMID: 27275026 PMCID: PMC4889982 DOI: 10.1093/plankt/fbv077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/21/2015] [Indexed: 05/25/2023]
Abstract
We determined the net rate of biogenic silica (bSiO2) production and estimated the diatom contribution to new production and organic matter export in the Costa Rica Dome during summer 2010. The shallow thermocline significantly reduces bSiO2 dissolution rates below the mixed layer, leading to significant enhancement of bSiO2 relative to organic matter (silicate-pump condition). This may explain why deep export of bSiO2 in this region is elevated by an order of magnitude relative to comparable systems. Diatom carbon, relative to autotrophic carbon, was low (<3%); however, the contribution of diatoms to new production averaged 3 and 13% using independent approaches. The 4-old discrepancy between methods may be explained by a low average C:Si ratio (∼1.4) for the net produced diatom C relative to the net produced bSiO2. We speculate that this low production ratio is not the result of reduced C, but may arise from a significant contribution of non-diatom silicifying organisms to bSiO2 production. The contribution of diatoms to organic matter export was minor (5.7%). These results, and those of the broader project, suggest substantial food-web transformation of diatom organic matter in the euphotic zone, which creates enriched bSiO2 relative to organic matter within the exported material.
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Affiliation(s)
- Jeffrey W. Krause
- Dauphin Island Sea Lab, 101 Bienville BLVD, Dauphin Island, AL 36528, USA
- University of South Alabama, Life Sciences Building Room 25, Mobile, AL 36688, USA
| | - Michael R. Stukel
- Florida State University, P.O. Box 3064520, Tallahassee, FL 32306-4520, USA
| | - Andrew G. Taylor
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - Darcy A. A. Taniguchi
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 54-1511A, Cambridge, MA 02142, USA
| | - Alain De Verneil
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - Michael R. Landry
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
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8
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Goes JI, Gomes HDR, Selph KE, Landry MR. Biological response of Costa Rica Dome phytoplankton to Light, Silicic acid and Trace metals. JOURNAL OF PLANKTON RESEARCH 2016; 38:290-304. [PMID: 27275031 PMCID: PMC4889990 DOI: 10.1093/plankt/fbv108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 11/19/2015] [Indexed: 05/25/2023]
Abstract
The Costa Rica Dome (CRD) is a unique open-ocean upwelling system, with picophytoplankton dominance of phytoplankton biomass and suppressed diatoms, yet paradoxically high export of biogenic silica. As a part of Flux and Zinc Experiments cruise in summer (June-July 2010), we conducted shipboard incubation experiments in the CRD to examine the potential roles of Si, Zn, Fe and light as regulating factors of phytoplankton biomass and community structure. Estimates of photosynthetic quantum yields revealed an extremely stressed phytoplankton population that responded positively to additions of silicic acid, iron and zinc and higher light conditions. Size-fractioned Chl a yielded the surprising result that picophytoplankton, as well as larger phytoplankton, responded most to treatments with added silicic acid incubated at high incident light (HL + Si). The combination of Si and HL also led to increases in cell sizes of picoplankton, notably in Synechococcus. Such a response, coupled with the recent discovery of significant intracellular accumulation of Si in some picophytoplankton, suggests that small phytoplankton could play a potentially important role in Si cycling in the CRD, which may help to explain its peculiar export characteristics.
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Affiliation(s)
- Joaquim I. Goes
- Lamont Doherty Earth Observatory at Columbia University, Palisades, New York, NY 10964, USA
| | - Helga do Rosario Gomes
- Lamont Doherty Earth Observatory at Columbia University, Palisades, New York, NY 10964, USA
| | - Karen E. Selph
- Department of Oceanography, University of Hawaii at Manoa, Honululu, HI 96822, USA
| | - Michael R. Landry
- Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
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9
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Stukel MR, Benitez-Nelson CR, Décima M, Taylor AG, Buchwald C, Landry MR. The biological pump in the Costa Rica Dome: an open-ocean upwelling system with high new production and low export. JOURNAL OF PLANKTON RESEARCH 2016; 38:348-365. [PMID: 27275035 PMCID: PMC4889986 DOI: 10.1093/plankt/fbv097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 10/25/2015] [Indexed: 05/31/2023]
Abstract
The Costa Rica Dome is a picophytoplankton-dominated, open-ocean upwelling system in the Eastern Tropical Pacific that overlies the ocean's largest oxygen minimum zone. To investigate the efficiency of the biological pump in this unique area, we used shallow (90-150 m) drifting sediment traps and 234Th:238U deficiency measurements to determine export fluxes of carbon, nitrogen and phosphorus in sinking particles. Simultaneous measurements of nitrate uptake and shallow water nitrification allowed us to assess the equilibrium balance of new and export production over a monthly timescale. While f-ratios (new:total production) were reasonably high (0.36 ± 0.12, mean ± standard deviation), export efficiencies were considerably lower. Sediment traps suggested e-ratios (export/14C-primary production) at 90-100 m ranging from 0.053 to 0.067. ThE-ratios (234Th disequilibrium-derived export) ranged from 0.038 to 0.088. C:N and N:P stoichiometries of sinking material were both greater than canonical (Redfield) ratios or measured C:N of suspended particulates, and they increased with depth, suggesting that both nitrogen and phosphorus were preferentially remineralized from sinking particles. Our results are consistent with an ecosystem in which mesozooplankton play a major role in energy transfer to higher trophic levels but are relatively inefficient in mediating vertical carbon flux to depth, leading to an imbalance between new production and sinking flux.
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Affiliation(s)
- Michael R. Stukel
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Claudia R. Benitez-Nelson
- Marine Science Program and Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Moira Décima
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92037, USA
- National Institute of Water and Atmospheric Research (NIWA), 301 Evans Bay Parade, Hataitai 6021, Wellington, New Zealand
| | - Andrew G. Taylor
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92037, USA
| | | | - Michael R. Landry
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92037, USA
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10
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Dreux Chappell P, Vedmati J, Selph KE, Cyr HA, Jenkins BD, Landry MR, Moffett JW. Preferential depletion of zinc within Costa Rica upwelling dome creates conditions for zinc co-limitation of primary production. JOURNAL OF PLANKTON RESEARCH 2016; 38:244-255. [PMID: 27275028 PMCID: PMC4889994 DOI: 10.1093/plankt/fbw018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 02/04/2016] [Indexed: 05/25/2023]
Abstract
The Costa Rica Dome (CRD) is a wind-driven feature characterized by high primary production and an unusual cyanobacterial bloom in surface waters. It is not clear whether this bloom arises from top-down or bottom-up processes. Several studies have argued that trace metal geochemistry within the CRD contributes to the composition of the phytoplankton assemblages, since cyanobacteria and eukaryotic phytoplankton have different transition metal requirements. Here, we report that total dissolved zinc (Zn) is significantly depleted relative to phosphate (P) and silicate (Si) within the upper water column of the CRD compared with other oceanic systems, and this may create conditions favorable for cyanobacteria, which have lower Zn requirements than their eukaryotic competitors. Shipboard grow-out experiments revealed that while Si was a limiting factor under our experimental conditions, additions of Si and either iron (Fe) or Zn led to higher biomass than Si additions alone. The addition of Fe and Zn alone did not lead to significant enhancements. Our results suggest that the depletion of Zn relative to P in upwelled waters may create conditions in the near-surface waters that favor phytoplankton with low Zn requirements, including cyanobacteria.
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Affiliation(s)
- P. Dreux Chappell
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA
- Department of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Jagruti Vedmati
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Karen E. Selph
- Department of Oceanography, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Heather A. Cyr
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA
| | - Bethany D. Jenkins
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA
| | - Michael R. Landry
- Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - James W. Moffett
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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Landry MR, Selph KE, Décima M, Gutiérrez-Rodríguez A, Stukel MR, Taylor AG, Pasulka AL. Phytoplankton production and grazing balances in the Costa Rica Dome. JOURNAL OF PLANKTON RESEARCH 2016; 38:366-379. [PMID: 27275036 PMCID: PMC4889984 DOI: 10.1093/plankt/fbv089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 09/15/2015] [Indexed: 05/10/2023]
Abstract
We investigated phytoplankton production rates and grazing fates in the Costa Rica Dome (CRD) during summer 2010 based on dilution depth profiles analyzed by flow cytometry and pigments and mesozooplankton grazing assessed by gut fluorescence. Three community production estimates, from 14C uptake (1025 ± 113 mg C m-2 day-1) and from dilution experiments analyzed for total Chla (990 ± 106 mg C m-2 day-1) and flow cytometry populations (862 ± 71 mg C m-2 day-1), exceeded regional ship-based values by 2-3-fold. Picophytoplankton accounted for 56% of community biomass and 39% of production. Production profiles extended deeper for Prochlorococcus (PRO) and picoeukaryotes than for Synechococcus (SYN) and larger eukaryotes, but 93% of total production occurred above 40 m. Microzooplankton consumed all PRO and SYN growth and two-third of total production. Positive net growth of larger eukaryotes in the upper 40 m was balanced by independently measured consumption by mesozooplankton. Among larger eukaryotes, diatoms contributed ∼3% to production. On the basis of this analysis, the CRD region is characterized by high production and grazing turnover, comparable with or higher than estimates for the eastern equatorial Pacific. The region nonetheless displays characteristics atypical of high productivity, such as picophytoplankton dominance and suppressed diatom roles.
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Affiliation(s)
- Michael R. Landry
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
- corresponding author:
| | - Karen E. Selph
- Department of Oceanography, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Moira Décima
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
- National Institute of Water and Atmospheric Research (NIWA), 301 Evans Bay Parade, Hataitai, Wellington 6021, New Zealand
| | - Andrés Gutiérrez-Rodríguez
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
- Centre National de la Recherche Scientifique and Universite Pierre et Marie Curie, Station Biologique, Roscoff 29680, France
| | - Michael R. Stukel
- Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Andrew G. Taylor
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - Alexis L. Pasulka
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
- Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
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Décima M, Landry MR, Stukel MR, Lopez-Lopez L, Krause JW. Mesozooplankton biomass and grazing in the Costa Rica Dome: amplifying variability through the plankton food web. JOURNAL OF PLANKTON RESEARCH 2016; 38:317-330. [PMID: 27275033 PMCID: PMC4889985 DOI: 10.1093/plankt/fbv091] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 09/24/2015] [Indexed: 05/25/2023]
Abstract
We investigated standing stocks and grazing rates of mesozooplankton assemblages in the Costa Rica Dome (CRD), an open-ocean upwelling ecosystem in the eastern tropical Pacific. While phytoplankton biomass in the CRD is dominated by picophytoplankton (<2-µm cells) with especially high concentrations of Synechococcus spp., we found high mesozooplankton biomass (∼5 g dry weight m-2) and grazing impact (12-50% integrated water column chlorophyll a), indicative of efficient food web transfer from primary producers to higher levels. In contrast to the relative uniformity in water-column chlorophyll a and mesozooplankton biomass, variability in herbivory was substantial, with lower rates in the central dome region and higher rates in areas offset from the dome center. While grazing rates were unrelated to total phytoplankton, correlations with cyanobacteria (negative) and biogenic SiO2 production (positive) suggest that partitioning of primary production among phytoplankton sizes contributes to the variability observed in mesozooplankton metrics. We propose that advection of upwelled waters away from the dome center is accompanied by changes in mesozooplankton composition and grazing rates, reflecting small changes within the primary producers. Small changes within the phytoplankton community resulting in large changes in the mesozooplankton suggest that the variability in lower trophic level dynamics was effectively amplified through the food web.
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Affiliation(s)
- Moira Décima
- Scripps Institution of Oceanography, 9500 Gilman Dr., LA Jolla, CA 92093-0227, USA; Present Address: National Institute of Water and Atmospheric Research (NIWA), 301 Evans Bay Parade, Hataitai 6021, Wellington, New Zealand
| | - Michael R Landry
- Scripps Institution of Oceanography , 9500 Gilman Dr., LA Jolla, CA 92093-0227 , USA
| | - Michael R Stukel
- Department of Earth, Ocean, and Atmospheri Science , Florida State University , Tallahasee, FL 32306 , USA
| | - Lucia Lopez-Lopez
- Ieo Centro Oceanografico De Santander , Promontorio San Martin S/N, 39004 Santander-Cantabria , Spain
| | - Jeffrey W Krause
- Dauphin Island Sea Lab , 101 Bienville Blvd, Dauphin Island, AL 36528 , USA
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Landry MR, De Verneil A, Goes JI, Moffett JW. Plankton dynamics and biogeochemical fluxes in the Costa Rica Dome: introduction to the CRD Flux and Zinc Experiments. JOURNAL OF PLANKTON RESEARCH 2016; 38:167-182. [PMID: 27275023 PMCID: PMC4889988 DOI: 10.1093/plankt/fbv103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 11/09/2015] [Indexed: 05/25/2023]
Abstract
The Costa Rica Dome (CRD) is an open-ocean upwelling system in the Eastern Tropical Pacific that overlies the ocean's largest oxygen minimum zone (OMZ). The region has unique characteristics, biomass dominance by picophytoplankton, suppressed diatoms, high biomass of higher consumers and presumptive trace metal limitation, but is poorly understood in terms of pelagic stock and process relationships, including productivity and production controls. Here, we describe the goals, project design, physical context and major findings of the Flux and Zinc Experiments cruise conducted in June-July 2010 to assess trophic flux relationships and elemental controls on phytoplankton in the CRD. Despite sampling during a year of suppressed summertime surface chlorophyll, cruise results show high productivity (∼1 g C m-2 day-1), high new production relative to export, balanced production and grazing, disproportionate biomass-specific productivity of large phytoplankton and high zooplankton stocks. Zinc concentrations are low in surface waters relative to phosphorous and silicate in other regions, providing conditions conducive to picophytoplankton, like Synechococcus, with low Zn requirements. Experiments nonetheless highlight phytoplankton limitation or co-limitation by silicic acid, driven by a strong silica pump that is linked to low dissolution of biogenic silica in the cold shallow thermocline of the lower euphotic zone.
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Affiliation(s)
- Michael R Landry
- Scripps Institution of Oceanography, University of California at San Diego , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA
| | - Alain De Verneil
- Scripps Institution of Oceanography, University of California at San Diego , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA
| | - Joaquim I Goes
- Department of Marine Biology and Paleoenvironment , Lamont Doherty Earth Observatory at Columbia University , Palisades, NY 10964 , USA
| | - James W Moffett
- Department of Biological Sciences , University of Southern California , Los Angeles, CA 90089 , USA
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Taylor AG, Landry MR, Freibott A, Selph KE, Gutiérrez-Rodríguez A. Patterns of microbial community biomass, composition and HPLC diagnostic pigments in the Costa Rica upwelling dome. JOURNAL OF PLANKTON RESEARCH 2016; 38:183-198. [PMID: 27275024 PMCID: PMC4889983 DOI: 10.1093/plankt/fbv086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 09/10/2015] [Indexed: 05/10/2023]
Abstract
We investigated biomass, size-structure, composition, depth distributions and spatial variability of the phytoplankton community in the Costa Rica Dome (CRD) in June-July 2010. Euphotic zone profiles were sampled daily during Lagrangian experiments in and out of the dome region, and the community was analyzed using a combination of digital epifluorescence microscopy, flow cytometry and HPLC pigments. The mean depth-integrated biomass of phytoplankton ranged 2-fold, from 1089 to 1858 mg C m-2 (mean ± SE = 1378 ± 112 mg C m-2), among 4 water parcels tracked for 4 days. Corresponding mean (±SE) integrated values for total chlorophyll a (Chl a) and the ratio of autotrophic carbon to Chl a were 24.1 ± 1.5 mg Chl a m-2 and 57.5 ± 3.4, respectively. Absolute and relative contributions of picophytoplankton (∼60%), Synechococcus (>33%) and Prochlorococcus (17%) to phytoplankton community biomass were highest in the central dome region, while >20 µm phytoplankton accounted for ≤10%, and diatoms <2%, of biomass in all areas. Nonetheless, autotrophic flagellates, dominated by dinoflagellates, exceeded biomass contributions of Synechococcus at all locations. Order-of-magnitude discrepancies in the relative contributions of diatoms (overestimated) and dinoflagellates (underestimated) based on diagnostic pigments relative to microscopy highlight potential significant biases associated with making community inferences from pigments.
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Affiliation(s)
- Andrew G. Taylor
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - Michael R. Landry
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
- corresponding author:
| | - Alexandra Freibott
- Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA
| | - Karen E. Selph
- Department of Oceanography, University of Hawaii At Manoa, Honolulu, HI 96822, USA
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