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Morrison BH, Jones JL, Dzwonkowski B, Krause JW. Tracking Vibrio: population dynamics and ecology of Vibrio parahaemolyticus and V. vulnificus in an Alabama estuary. Microbiol Spectr 2024; 12:e0367423. [PMID: 38578091 DOI: 10.1128/spectrum.03674-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/05/2024] [Indexed: 04/06/2024] Open
Abstract
Vibrio is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures often involve contact with vectors of pathogenic Vibrio spp. (e.g., consuming raw shellfish). High rates of mortality from certain Vibrio spp. infections demonstrate the need for an improved understanding of Vibrio spp. dynamics in estuarine regions. Our study assessed meteorological, hydrographic, and biological correlates of Vibrio parahaemolyticus and V. vulnificus at 10 sites in the Eastern Mississippi Sound System (EMSS) from April to October 2019. During the sampling period, median abundances of V. parahaemolyticus and V. vulnificus were 2.31 log MPN/L and 2.90 log MPN/L, respectively. Vibrio spp. dynamics were largely driven by site-based variation, with sites closest to freshwater inputs having the highest abundances. The E-W wind scalar, which affects Ekman transport, was a novel Vibrio spp. correlate observed. A potential salinity effect on bacterial-particle associations was identified, where V. vulnificus was associated with larger particles in conditions outside of their optimal salinity. Additionally, V. vulnificus abundances were correlated to those of harmful algal species that did not dominate community chlorophyll. Correlates from this study may be used to inform the next iteration of regionally predictive Vibrio models and may lend additional insight to Vibrio spp. ecology in similar systems. IMPORTANCE Vibrio spp. are bacteria found in estuaries worldwide; some species can cause illness and infections in humans. Relationships between Vibrio spp. abundance, salinity, and temperature are well documented, but correlations to other environmental parameters are less understood. This study identifies unique correlates (e.g., E-W wind scalar and harmful algal species) that could potentially inform the next iteration of predictive Vibrio models for the EMSS region. Additionally, these correlates may allow existing environmental monitoring efforts to be leveraged in providing data inputs for future Vibrio risk models. An observed correlation between salinity and V. vulnificus/particle-size associations suggests that predicted environmental changes may affect the abundance of Vibrio spp. in certain reservoirs, which may alter which vectors present the greatest vibrio risk.
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Affiliation(s)
- Blair H Morrison
- Dauphin Island Sea Lab, Dauphin Island, Alabama, USA
- Stokes School of Marine and Environmental Sciences, University of South Alabama, Mobile, Alabama, USA
- FDA, Division of Seafood Science and Technology, Gulf Coast Seafood Laboratory, Dauphin Island, Alabama, USA
| | - Jessica L Jones
- FDA, Division of Seafood Science and Technology, Gulf Coast Seafood Laboratory, Dauphin Island, Alabama, USA
| | - Brian Dzwonkowski
- Dauphin Island Sea Lab, Dauphin Island, Alabama, USA
- Stokes School of Marine and Environmental Sciences, University of South Alabama, Mobile, Alabama, USA
| | - Jeffrey W Krause
- Dauphin Island Sea Lab, Dauphin Island, Alabama, USA
- Stokes School of Marine and Environmental Sciences, University of South Alabama, Mobile, Alabama, USA
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2
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Marquez IA, Abraham A, Krause JW. Organic polymer consumption facilitates domoic acid entry into the marine food web without direct ingestion of Pseudo-nitzschia. Harmful Algae 2020; 98:101891. [PMID: 33129467 DOI: 10.1016/j.hal.2020.101891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 08/04/2020] [Accepted: 08/09/2020] [Indexed: 06/11/2023]
Abstract
Domoic acid (DA) is a neurotoxin produced by diatoms from the genera Pseudo-nitzschia and Nitzschia. DA is transferred through the food web when consumed by organisms such as copepods (e.g., Acartia tonsa). DA bioaccumulates in higher trophic levels and poses a threat to human health through amnesic shellfish poisoning. Laboratory experiments using a DA reference standard demonstrated that mild turbulence facilitates formation of organic polymer aggregates >0.6 µm in-vivo that can scavenge dissolved DA (dDA). Using A. tonsa, we demonstrate that DA can be assimilated through consumption of these organic polymers which scavenged dDA -a pathway which does not require direct ingestion of the toxin-producer Pseudo-nitzschia. In filtered seawater with spiked DA, copepods accumulated 24.8 ± 4.7 pg DA copepod-1 (2.1 ppm) on average by consuming organic polymers. This was validated in one out of five experiments using ambient DA concentrations. Copepods were suspended in particle-free seawater and accumulated 14.4 ± 3.8 pg DA copepod-1 (1.20 ppm), and in particle-concentrated seawater they accumulated 40.9 ± 3.8 pg DA copepod-1 (3.42 ppm). Data from this experiment suggests that ~34% of the total assimilated DA entered via an organic polymer-bound DA pathway. This experiment had the highest Pseudo-nitzschia spp. abundance (~225,000 cells L - 1) and cellular toxin quota, up to 0.88 pg DA cell-1, relative to the other four ambient DA experiments. These results demonstrate the potential for DA to enter the marine food web through an alternate pathway and may have considerable implications to understanding the flow of DA through marine food webs, and how we monitor DA and its potential vectors into the food web.
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Affiliation(s)
- Israel A Marquez
- Department of Marine Sciences, University of South Alabama, 307N. University Blvd. Mobile, AL 36688, United States; Dauphin Island Sea Lab, 101 Bienville Blvd Dauphin Island, AL 36528, United States.
| | - Ann Abraham
- FDA, Division of Seafood Science and Technology, Gulf Coast Seafood Laboratory, 1 Iberville Dr. Dauphin Island, AL 36528, United States.
| | - Jeffrey W Krause
- Department of Marine Sciences, University of South Alabama, 307N. University Blvd. Mobile, AL 36688, United States; Dauphin Island Sea Lab, 101 Bienville Blvd Dauphin Island, AL 36528, United States.
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3
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Krause JW, Schulz IK, Rowe KA, Dobbins W, Winding MHS, Sejr MK, Duarte CM, Agustí S. Silicic acid limitation drives bloom termination and potential carbon sequestration in an Arctic bloom. Sci Rep 2019; 9:8149. [PMID: 31148569 PMCID: PMC6544819 DOI: 10.1038/s41598-019-44587-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/17/2019] [Indexed: 11/09/2022] Open
Abstract
The spring diatom bloom in the Arctic Ocean accounts for significant annual primary production leading to the most rapid annual drawdown of water-column pCO2. Late-winter waters in the Atlantic Arctic & Subarctic Provinces (AASP) have lower silicic acid concentrations than nitrate, which suggests diatom blooms may deplete Si before N. Here we test a facet of the hypothesis that silicic acid limitation terminates the spring diatom bloom in the AASP and the sinking of the senescent and dead diatoms helps drive carbon sequestration. During a 6-week study, diatoms bloomed and progressively consumed silicic acid to where it limited their growth. The onset of growth limitation was concurrent with the minimum pCO2 in the surface waters and increases in both the proportion of dead diatoms and the diatom assemblage sedimentation rate. Data reanalysis within the AASP shows a highly significant and positive correlation between silicic acid and pCO2 in the surface waters, but no significant relationship with nitrate and pCO2 was observed unless data were smoothed. Therefore, understanding the future of the AASP spring diatom bloom requires models that explicitly consider changes in silicic acid supply as a driver of this process.
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Affiliation(s)
- Jeffrey W Krause
- Dauphin Island Sea Lab, Dauphin Island, AL, USA. .,Department of Marine Sciences, University of South Alabama, Mobile, AL, USA.
| | - Isabelle K Schulz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Katherine A Rowe
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Mie H S Winding
- Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
| | - Mikael K Sejr
- Arctic Research Center (ARC), Aarhus University, Aarhus, Denmark
| | - Carlos M Duarte
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Arctic Research Center (ARC), Aarhus University, Aarhus, Denmark
| | - Susana Agustí
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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4
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McNair HM, Brzezinski MA, Krause JW. Diatom populations in an upwelling environment decrease silica content to avoid growth limitation. Environ Microbiol 2018; 20:4184-4193. [PMID: 30253028 DOI: 10.1111/1462-2920.14431] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 09/21/2018] [Accepted: 09/22/2018] [Indexed: 11/30/2022]
Abstract
A mix of adaptive strategies enable diatoms to sustain rapid growth in dynamic ocean regions, making diatoms one of the most productive primary producers in the world. We illustrate one such strategy off coastal California that facilitates continued, high, cell division rates despite silicic acid stress. Using a fluorescent dye to measure single-cell diatom silica production rates, silicification (silica per unit area) and growth rates we show diatoms decrease silicification and maintain growth rate when silicon concentration limits silica production rates. While this physiological response to silicon stress was similar across taxa, in situ silicic acid concentration limited silica production rates by varying degrees for taxa within the same community. Despite this variability among taxa, silicon stress did not alter the contribution of specific taxa to total community silica production or to community composition. Maintenance of division rate at the expense of frustule thickness decreases cell density which could affect regional biogeochemical cycles. The reduction in frustule silicification also creates an ecological tradeoff: thinner frustules increase susceptibility to predation but reducing Si quotas maximizes cell abundance for a given pulse of silicic acid, thereby favouring a larger eventual population size which facilitates diatom persistence in habitats with pulsed resource supplies.
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Affiliation(s)
- Heather M McNair
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Mark A Brzezinski
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA.,Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Jeffrey W Krause
- Dauphin Island Sea Lab, University of South Alabama, Mobile, AL, USA.,Department of Marine Sciences, University of South Alabama, Mobile, AL, USA
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McNair HM, Brzezinski MA, Till CP, Krause JW. Taxon-specific contributions to silica production in natural diatom assemblages. Limnol Oceanogr 2018; 63:1056-1075. [PMID: 29937577 PMCID: PMC6007990 DOI: 10.1002/lno.10754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The metabolic activity and growth of phytoplankton taxa drives their ecological function and contribution to biogeochemical processes. We present the first quantitative, taxon-resolved silica production rates, growth rates, and silica content estimates for co-occurring diatoms along two cross-shelf transects off the California coast using the fluorescent tracer PDMPO (2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole), and confocal microscopy. Taxon contribution to total diatom community silica production was predominantly a function of the surface area of new frustule that each taxon created as opposed to cell abundance or frustule thickness. The influential role of surface area made large diatoms disproportionately important to community silica production over short time scales (<1 d). In some cases, large taxa that comprised only ~15% of numerical cell abundance accounted for over 50% of total community silica production. Over longer time scales relevant to bloom dynamics, the importance of surface area declines and growth rate becomes the dominant influence on contribution to production. The relative importance of surface area and growth rate in relation to silica production was modeled as the time needed for a smaller, faster-growing taxon to create more surface area than a larger, slower-growing taxon. Differences in growth rate between the taxa effected the model outcome more than differences in surface area. Shifts in relative silica production among taxa are time restricted by finite resources that limit the duration of a bloom. These patterns offer clues as to how taxa respond to their environment and the consequences for both species succession and the potential diatom contribution to elemental cycling.
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Affiliation(s)
- Heather M McNair
- Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, California, United States of America
| | - Mark A Brzezinski
- Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, California, United States of America
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Claire P Till
- Chemistry Department, Humboldt State University, Arcata, California, United States of America
| | - Jeffrey W Krause
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
- Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America
- Department of Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America
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6
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Brzezinski MA, Krause JW, Baines SB, Collier JL, Ohnemus DC, Twining BS. Patterns and regulation of silicon accumulation in Synechococcus spp. J Phycol 2017; 53:746-761. [PMID: 28457002 DOI: 10.1111/jpy.12545] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
Six clones of the marine cyanobacterium Synechococcus, representing four major clades, were all found to contain significant amounts of silicon in culture. Growth rate was unaffected by silicic acid, Si(OH)4 , concentration between 1 and 120 μM suggesting that Synechococcus lacks an obligate need for silicon (Si). Strains contained two major pools of Si: an aqueous soluble and an aqueous insoluble pool. Soluble pool sizes correspond to estimated intracellular dissolved Si concentrations of 2-24 mM, which would be thermodynamically unstable implying the binding of intracellular soluble Si to organic ligands. The Si content of all clones was inversely related to growth rate and increased with higher [Si(OH)4 ] in the growth medium. Accumulation rates showed a unique bilinear response to increasing [Si(OH)4 ] from 1 to 500 μM with the rate of Si acquisition increasing abruptly between 80 and 100 μM Si(OH)4 . Although these linear responses imply some form of diffusion-mediated transport, Si uptake rates at low Si (~1 μM Si) were inhibited by orthophosphate, suggesting a role of phosphate transporters in Si acquisition. Theoretical calculations imply that observed Si acquisition rates are too rapid to be supported by lipid-solubility diffusion of Si through the plasmalemma; however, facilitated diffusion involving membrane protein channels may suffice. The data are used to construct a working model of the mechanisms governing the Si content and rate of Si acquisition in Synechococcus.
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Affiliation(s)
- Mark A Brzezinski
- Marine Science Institute and the Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, California, USA
| | - Jeffrey W Krause
- Dauphin Island Sea Lab, Dauphin Island, Alabama, USA
- Department of Marine Sciences, University of South Alabama, Mobile, Alabama, USA
| | - Stephen B Baines
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Jackie L Collier
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Daniel C Ohnemus
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, 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. J Plankton Res 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] [What about the content of this article? (0)] [Affiliation(s)] [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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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. J Plankton Res 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] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Abstract
Diatoms require silicic acid to construct ornately detailed cell walls called frustules. The growth and geographic distribution of diatoms is often controlled by the availability of silicic acid. Analytical methods exist to assess diatom community biogenic silica (bSiO2) production, but partitioning production among taxa has been largely qualitative. We present a method for the quantitative analysis of taxa-specific silica production through labeling diatoms with the fluorescent dye PDMPO [2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole]. To make PDMPO a quantitative tool: diatom frustules were solubilized to assess the total diatom community incorporation by quantitation of PDMPO fluorescence using a fluorometer, and laser confocal microscopy was used to quantify the fluorescence of PDMPO in single diatom cells. We created a fluorescence standard to intercalibrate the raw fluorescence signals of the fluorometer and microscope and to determine the fluorescence per mole of PDMPO. PDMPO incorporation was converted to silica production using diatom bSiO2:PDMPO incorporation ratios which varied systematically with silicic acid concentration. Above 3 μM Si(OH)4, bSiO2:PDMPO was constant and PDMPO incorporation was converted to silica production using a mole ratio of 2,916 as determined from cultures. Below 3 μM, the ratio was a linear function of [Si(OH)4] (bSiO2:PDMPO = 912.6 × [Si(OH)4]), as determined using data from two oceanographic cruises. Field evaluation of the method showed that total community PDMPO incorporation generally agreed to within 30% of radioisotope-determined silica production. This PDMPO method has the potential to be a powerful tool for understanding physiology, silicification and resource competition among diatom taxa.
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Affiliation(s)
- Heather M. McNair
- Department of Ecology Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, United States of America
| | - Mark A. Brzezinski
- Department of Ecology Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, United States of America
- Marine Science Institute, University of California, Santa Barbara,
California 93106, United States of America
| | - Jeffrey W. Krause
- Marine Science Institute, University of California, Santa Barbara,
California 93106, United States of America
- Dauphin Island Sea Lab, Dauphin Island, Alabama 36528, United States
of America
- Department of Marine Sciences, University of South Alabama, Mobile,
Alabama 36688, United States of America
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Abstract
Bilateral recurrent laryngeal nerve (RLN) palsies result in dyspnea and often require further surgery to secure an adequate airway for safe respiration. The present study was devised to determine a predictive value of laryngeal electromyography (LEMG) and if it has therapeutic consequences. In a retrospective study of 63 patients with bilateral recurrent laryngeal nerve palsies after thyroid gland surgery we compared the results of LEMG from the thyroarytenoid muscles with the spontaneous recovery rate of vocal cord mobility. A tracheostomy had to be performed in 18 patients because of unsafe dyspnea, while a unilateral lateral cord fixation had to be carried out in 20 patients. Primary thyroidectomies as treatment for benign goiters showed spontaneous normalization of unilateral or bilateral vocal cord mobility in 75% of cases versus 36% after revision thyroidectomies. Single LEMG correctly predicted prognosis in 78% of patients. In all, LEMG was found to be of value in the assessment of bilateral recurrent laryngeal nerve palsies. Findings also showed that a lateral cord fixation should be planned after a 9-month waiting period. When a patient refuses a tracheostomy lateral cord fixation can be performed at an earlier time, with the use of repeated LEMGs to predict whether or not a corrective surgery.
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