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Rogers AD, Frinault BAV, Barnes DKA, Bindoff NL, Downie R, Ducklow HW, Friedlaender AS, Hart T, Hill SL, Hofmann EE, Linse K, McMahon CR, Murphy EJ, Pakhomov EA, Reygondeau G, Staniland IJ, Wolf-Gladrow DA, Wright RM. Antarctic Futures: An Assessment of Climate-Driven Changes in Ecosystem Structure, Function, and Service Provisioning in the Southern Ocean. Ann Rev Mar Sci 2020; 12:87-120. [PMID: 31337252 DOI: 10.1146/annurev-marine-010419-011028] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this article, we analyze the impacts of climate change on Antarctic marine ecosystems. Observations demonstrate large-scale changes in the physical variables and circulation of the Southern Ocean driven by warming, stratospheric ozone depletion, and a positive Southern Annular Mode. Alterations in the physical environment are driving change through all levels of Antarctic marine food webs, which differ regionally. The distributions of key species, such as Antarctic krill, are also changing. Differential responses among predators reflect differences in species ecology. The impacts of climate change on Antarctic biodiversity will likely vary for different communities and depend on species range. Coastal communities and those of sub-Antarctic islands, especially range-restricted endemic communities, will likely suffer the greatest negative consequences of climate change. Simultaneously, ecosystem services in the Southern Ocean will likely increase. Such decoupling of ecosystem services and endemic species will require consideration in the management of human activities such as fishing in Antarctic marine ecosystems.
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Affiliation(s)
- A D Rogers
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
- REV Ocean, 1366 Lysaker, Norway
| | - B A V Frinault
- School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, United Kingdom
| | - D K A Barnes
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - N L Bindoff
- Antarctic Climate and Ecosystems Cooperative Research Centre and CSIRO Oceans and Atmospheres, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - R Downie
- WWF, Living Planet Centre, Surrey GU21 4LL, United Kingdom
| | - H W Ducklow
- Lamont-Doherty Earth Observatory and Department of Earth and Environmental Sciences, Columbia University, Palisades, New York 10964-8000, USA
| | - A S Friedlaender
- Institute for Marine Sciences, University of California, Santa Cruz, California 95060, USA
| | - T Hart
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom;
| | - S L Hill
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - E E Hofmann
- Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, Virginia 23508, USA
| | - K Linse
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - C R McMahon
- Integrated Marine Observing System Animal Tracking Facility, Sydney Institute of Marine Science, Sydney, New South Wales 2088, Australia
| | - E J Murphy
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - E A Pakhomov
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Aquatic Ecosystems Research Lab, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - G Reygondeau
- Aquatic Ecosystems Research Lab, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - I J Staniland
- British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, United Kingdom
| | - D A Wolf-Gladrow
- Alfred-Wegener-Institut Helmholtz Zentrum für Polar- und Meeresforschung (AWI), 27570 Bremerhaven, Germany
| | - R M Wright
- Tyndall Centre, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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Abstract
Recent determinations of high production rates (up to 30 percent of primary production in surface waters) implicate free-living marine bacterioplankton as a link in a "microbial loop" that supplements phytoplankton as food for herbivores. An enclosed water column of 300 cubic meters was used to test the microbial loop hypothesis by following the fate of carbon-14-labeled bacterioplankton for over 50 days. Only 2 percent of the label initially fixed from carbon-14-labeled glucose by bacteria was present in larger organisms after 13 days, at which time about 20 percent of the total label added remained in the particulate fraction. Most of the label appeared to pass directly from particles smaller than 1 micrometer (heterotrophic bacterioplankton and some bacteriovores) to respired labeled carbon dioxide or to regenerated dissolved organic carbon-14. Secondary (and, by implication, primary) production by organisms smaller than 1 micrometer may not be an important food source in marine food chains. Bacterioplankton can be a sink for carbon in planktonic food webs and may serve principally as agents of nutrient regeneration rather than as food.
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Ducklow HW, Kirchman DL, Rowe GT. Production and vertical flux of attached bacteria in the hudson river plume of the new york bight as studied with floating sediment traps. Appl Environ Microbiol 2010; 43:769-76. [PMID: 16345987 PMCID: PMC241916 DOI: 10.1128/aem.43.4.769-776.1982] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated the growth and vertical flux of attached bacteria with floating sediment traps in the Hudson River Plume of the New York Bight during the spring diatom blooms. Traps were floated at the base of the mixed layer (ca. 10 m) for 1-day periods. After recovery, we measured bacterial abundance and rates of [methyl-H]thymidine incorporation in the trap samples. The vertical flux of attached bacteria was estimated with a model formulated to distinguish between bacterial accumulation in traps due to in situ growth and that due to vertical flux. Attached bacterial flux ranged from 0.6 x 10 to 2.0 x 10 cells m day, and attached bacterial settling rates of 0.1 to 1.0 m day were observed during periods of vertical particulate organic carbon flux ranging from 254 to 1,267 mg of C m day. In situ growth of bacteria in sediment traps was unimportant as a source of bacterial increase when compared with vertical flux during our study. The vertical flux of attached bacteria removed 3 to 67% of the total daily bacterial production from the water column. Particulate organic carbon is not significantly mineralized by attached bacteria during its descent to the sea floor in the plume area during this period, when water temperature and grazing rates are at their annual minima.
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Affiliation(s)
- H W Ducklow
- Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964; Division of Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 ; and Division of Oceanographic Sciences, Brookhaven National Laboratory, Upton, New York 11973
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Montes-Hugo M, Doney SC, Ducklow HW, Fraser W, Martinson D, Stammerjohn SE, Schofield O. Recent Changes in Phytoplankton Communities Associated with Rapid Regional Climate Change Along the Western Antarctic Peninsula. Science 2009; 323:1470-3. [DOI: 10.1126/science.1164533] [Citation(s) in RCA: 488] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Abstract
The importance of resource limitation in controlling bacterial growth in the high-nutrient, low-chlorophyll (HNLC) region of the Southern Ocean was experimentally determined during February and March 1998. Organic- and inorganic-nutrient enrichment experiments were performed between 42 degrees S and 55 degrees S along 141 degrees E. Bacterial abundance, mean cell volume, and [(3)H]thymidine and [(3)H]leucine incorporation were measured during 4- to 5-day incubations. Bacterial biomass, production, and rates of growth all responded to organic enrichments in three of the four experiments. These results indicate that bacterial growth was constrained primarily by the availability of dissolved organic matter. Bacterial growth in the subtropical front, subantarctic zone, and subantarctic front responded most favorably to additions of dissolved free amino acids or glucose plus ammonium. Bacterial growth in these regions may be limited by input of both organic matter and reduced nitrogen. Unlike similar experimental results in other HNLC regions (subarctic and equatorial Pacific), growth stimulation of bacteria in the Southern Ocean resulted in significant biomass accumulation, apparently by stimulating bacterial growth in excess of removal processes. Bacterial growth was relatively unchanged by additions of iron alone; however, additions of glucose plus iron resulted in substantial increases in rates of bacterial growth and biomass accumulation. These results imply that bacterial growth efficiency and nitrogen utilization may be partly constrained by iron availability in the HNLC Southern Ocean.
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Affiliation(s)
- M J Church
- School of Marine Science, The College of William and Mary, Gloucester Point, Virginia 23062-1346, USA.
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Shiah FK, Ducklow HW. Regulation of bacterial abundance and production by substrate supply and bacterivory: A mesocosm study. Microb Ecol 1995; 30:239-255. [PMID: 24185562 DOI: 10.1007/bf00171932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/1994] [Revised: 01/19/1995] [Indexed: 06/02/2023]
Abstract
Daily bacterial abundance and production, heterotrophic nanoflagellates (HNAN) abundance, chlorophyll, and NH4 (+) concentrations were measured in four indoor 400-liter tanks over 13 days to study the role of heterotrophic bacterioplankton in NH4 (-) cycling and to identify the succession of top-down and bottom-up processes in regulating bacterial biomass and production. Ammonium (NH4 (+)) was added to these four tanks daily whenever its concentration in tanks was < 4 μM. Tanks 3 and 4 (treatment tanks) also received 4 μM of glucose daily till the end of experiment. Lower NH4 (-) concentrations and higher bacterial specific growth rate and production observed in the treatment tanks indicated that bacteria might take up NH4+ with the addition of labile organic carbon. Bacterial biomass was controlled by substrate supply and HNAN grazing from day 7 to day 13, when phytoplankton declined. Bacterial size distribution patterns were determined primarily by substrate supply, with HNAN grazing playing a less important role. Certain variabilities existed between the control (and the treatment) tanks. These inconsistencies could be due to differences in time of expression of given variables. However, the total amounts of bacterial biomass accumulated in the four tanks were very similar. The inconsistency in timing of expression of variables was probably due to different initial conditions in each tank. The ecological meanings of the inconsistency in timing and overall consistency were discussed.
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Affiliation(s)
- F K Shiah
- Horn Point Environmental Laboratory, 21613, Cambridge, MD, USA
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Abstract
Models of the microbial food web have their origin in the debate over the importance of bacteria as an energetic subsidy for higher trophic levels leading to harvestable fisheries. Conceptualization of the microbial food web preceded numerical models by 10-15 years. Pomeroy's work was central to both efforts. Elements necessary for informative and comprehensive models of microbial loops in plankton communities include coupled carbon and nitrogen flows utilizing a size-based approach to structuring and parameterizing the food web. Realistic formulation of nitrogen flows requires recognition that both nitrogenous and nonnitrogenous organic matter are important substrates for bacteria. Nitrogen regeneration driven by simple mass-specific excretion constants seems to overestimate the role of bacteria in the regeneration process. Quantitative assessment of the link-sink question, in which the original loop models are grounded, requires sophisticated analysis of size-based trophic structures. The effects of recycling complicate calculation of the link between bacteria or dissolved organic matter and mesozooplankton, and indirect effects show that the link might be much stronger than simple analyses have suggested. Examples drawn from a series of oceanic mixed layer plankton models are used to illustrate some of these points. Single-size class models related to traditional P-Z-N approaches are incapable of simulating bacterial biomass cycles in some locations (e.g., Bermuda) but appear to be adequate for more strongly seasonal regimes at higher latitudes.
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Affiliation(s)
- H W Ducklow
- Department of Chemistry, Woods Hole Oceanographic Institution, 02543, Woods Hole, Massachusetts, USA,
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Ducklow HW, Kirchman DL, Quinby HL. Bacterioplankton cell growth and macromolecular synthesis in seawater cultures during the North Atlantic Spring Phytoplankton Bloom, May, 1989. Microb Ecol 1992; 24:125-144. [PMID: 24193132 DOI: 10.1007/bf00174450] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/1992] [Revised: 06/23/1992] [Indexed: 06/02/2023]
Abstract
We performed a series of seawater culture experiments on surface mixed layer samples during the spring phytoplankton bloom in the North Atlantic Ocean. Diluted (20% unfiltered + 80% 0.22 μm filtered) and untreated "whole" seawater samples were incubated up to 40 hour and sampled periodically for cell numbers, biovolume, and incorporation of (3)H-thymidine and -leucine. Abundance and biovolume increased exponentially at similar rates in diluted and whole samples, suggesting that removal by bacteriovores was low compared with growth. The exponential increase in biovolume was due to increases in cell numbers and mean cell volume. Generation times (i.e., 0.693/μ) averaged 36-53 hour in these surface (10 m) samples. Ninety percent of the tritiated thymidine incorporation (TTI) into cold trichloroacetic acid-insoluble cell fractions was recovered after extraction with NaOH and phenolchloroform, indicating that catabolism of thymidine and its appearance in RNA or protein was very low. The percentage of thymidine recovered in DNA did not change over the 40 hour of incubation and was the same as in water column samples. Rates of thymidine and leucine incorporation also increased exponentially. Incorporation rates tended to increase more rapidly than cell numbers or biovolume, though the differences were not significantly different, due to the small number of samples and variability over the time courses. Differential rates of increase in cellular properties during growth might indicate a lack of coupling between incorporation and production over time scales of hours-days. This in turn may reflect unbalanced growth of bacterial assemblages, which is an adaptation to variable conditions in the upper ocean in this season. Nonequality of rate constants for cells and incorporation yields conversion factors that are either higher or lower than would be calculated from balanced growth (i.e., rates of increase in numbers and incorporation rates equal), depending on the calculation approach chosen. An alternative approach to calculating conversion factors (the modified derivative approach) is proposed, which is insensitive to differential rates of increase of abundance and incorporation.
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Affiliation(s)
- H W Ducklow
- Horn Point Environmental Laboratory, University of Maryland-CEES, 21613, Cambridge, MD
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Boicourt WC, Chao SY, Ducklow HW, Glibert PM, Malone TC, Roman MR, Sanford LP, Fuhrman JA, Garside C, Garvine RW. Physics and microbial ecology of a buoyant estuarine plume on the continental shelf. ACTA ACUST UNITED AC 1987. [DOI: 10.1029/eo068i031p00666] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ducklow HW, Clausen K, Mitchell R. Ecology of bacterial communities in the schistosomiasis vector snailBiomphalaria glabrata. Microb Ecol 1981; 7:253-274. [PMID: 24227500 DOI: 10.1007/bf02010308] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The internal colony-forming bacterial flora of the schistosome intermediate host snailBiomphalaria glabrata (Say) has been characterized in ca. 500 individual snails from Puerto Rico, Guadeloupe, and St. Lucia, and from laboratory aquaria. Freshly captured wild snails harbor 2-40×10(6) CFU·g(-1), and healthy aquarium snails harbor 4-16×10(7) CFU·g(-1), whereas moribund individuals have 4-10 times as many bacteria as healthy individuals from the same habitats.Pseudomonas spp. are the most common predominant bacteria in normal snails, whereasAcinetobacter, Aeromonas, andMoraxella spp. predominate in moribund snails. External bacterial populations in water appear to have little effect on the composition and size of the flora in any snail. In addition to normal (healthy) and moribund snails, a third group of snails has been distinguished on the basis of internal bacterial density and predominating genera. These "high-density" snails may have undergone stresses and may harbor opportunistic pathogens. The microfloras of wild and laboratory-reared snails can be altered and stimulated to increase in density by crowding the snails or treating them with antibiotics.
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Affiliation(s)
- H W Ducklow
- Department of Marine Biology, Lamont-Doherty Geological Observatory of Columbia University, 10964, Palisades, New York, USA
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Ducklow HW, Tarraza HM, Mitchell R. Experimental pathogenicity of Vibrio parahaemolyticus for the schistosome-bearing snail Biomphalaria glabrata. Can J Microbiol 1980; 26:503-6. [PMID: 7378944 DOI: 10.1139/m80-084] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The bacterium Vibrio parahaemolyticus was found to be pathogenic for the schistosome intermediate host Biomphalaria glabrata (Say). When administered topically, a nonenteritis-associated strain of the bacterium had an LD50 (median lethal dose) of 6.8 x 10(7) cells per snail. A 5% trichloroacetic acid (TCA) extract from V. parahaemolyticus was found to kill B. glabrata. Sublethal effects of V. parahaemolyticus include shell deterioration and increased heart rate. Both albino aquarium populations and naturally occurring Puerto Rican wild populations of B. glabrata are susceptible to V. parahaemolyticus. This bacterium provides a useful model for the study of pathogens and biological control of schistosome vector snails, since it causes significant mortality and is recognized as a pathogen of other invertebrates.
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Abstract
The aerobic heterotrophic bacterial flora in over 200 individuals from 10 wild populations and 3 laboratory colonies of the schistosome vector snail Biomphalaria glabrata was examined. Internal bacterial densities were inversely proportional to snail size and were higher in stressed and laboratory-reared snails. The numerically predominant bacterial genera in individual snails included Pseudomonas, Acinetobacter, Aeromonas, Vibrio, and several members of the Enterobacteriaceae. Enterobacteriaceae seldom predominated in laboratory colonies. Our data suggest that Vibrio extorquens and a Pasteurella sp. tend to predominate in high-bacterial-density snails. These snails may be compromised and may harbor opportunistic snail pathogens.
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Ducklow HW, Mitchell R. Observations on naturally and artificially diseased tropical corals: A scanning electron microscope study. Microb Ecol 1979; 5:215-223. [PMID: 24232495 DOI: 10.1007/bf02013528] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Scanning electron microscopic (SEM) observations of naturally and artificially diseased corals reveal that the disease is characterized by a filamentous matrix of cyanobacterial andBeggiatoa filaments. Spiral bacteria are commonly embedded in the matrix. The artificial disease is not manifested as the characteristic "black line disease" and does not contain filaments of cyanobacteria. This suggests that cyanobacteria are necessary for the black line phenomenon. The colorless, sulfide-oxidizing bacteriumBeggiatoa, however, is always associated with the disease.
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Affiliation(s)
- H W Ducklow
- Laboratory of Microbial Ecology, Harvard University, 02138, Cambridge, Massachusetts
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