DOCSLIB.ORG

Comparison of Pelagic and Nepheloid Layer Marine Snow: Implications for Carbon Cycling

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Comparison of Pelagic and Nepheloid Layer Marine Snow: Implications for Carbon Cycling ELSEVIER Marine Geology 150 (1998) 39±50 Comparison of pelagic and nepheloid layer marine snow: implications for carbon cycling Barbara Ransom a,Ł,KevinF.Sheab, Patti Jo Burkett b, Richard H. Bennett c, Roy Baerwald d a Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0220, USA b Naval Research Laboratory, Stennis Space Center, MS 39529, USA c SEAPROBE Inc., 01 Pine Street, Picayune, MS 39566, USA d Department of Biology, University of New Orleans, New Orleans, LO 70148, USA Received 2 June 1997; accepted 8 May 1998 Abstract Marine snow from upper and mid-water (i.e., pelagic) depths on the California margin is texturally and compositionally different from that traveling in the nepheloid layer. Transmission electron microscopy shows that pelagic marine snow consists primarily of bioclasts (e.g., diatom frustules, foram tests), organic matter, and microbes. These components are entrained as discrete particles or small aggregates .Ä 10 mm in diameter) in a loose network of exocellular, muco-polysaccharide material. Clays are infrequent but, when present, are constituents of comparatively compact organic-rich microaggregates. Microbes are abundant and appear to decrease in number with increasing water depth. In contrast, marine snow aggregates collected from just above the sea ¯oor in the nepheloid layer are assemblages of clay particles, clay ¯ocs, and relatively dense clay±organic-rich microaggregates in an exocellular organic matrix. Bioclasts and microorganisms occur only rarely. The prevalence of clay±organic-rich aggregates in the nepheloid layer suggests that, prior to ®nal deposition and burial, marine snow from the pelagic zone is subject to disaggregation and recombination with terrigenous detrital material near or at the sea ¯oor. Results have signi®cant implications for the accumulation and burial rates of organic carbon on continental margins and the aging and bioavailability of sedimentary organic matter. Samples examined were collected offshore of northern and central California. 1998 Elsevier Science B.V. All rights reserved. Keywords: nepheloid layer; marine snow; organic carbon; continental margin; TEM 1. Introduction has focused on surface to mid-water column ag- gregate production and the rates and variability of Marine snow, the population of marine aggre- organic carbon transport to the sea ¯oor (see review gates with diameters greater than 5 mm, is the in Alldredge and Silver, 1988). Recent research now primary means by which organic matter is trans- suggests that marine snow aggregates may also play ported down through the water column (Fowler and an important role in the development of sediment Knauer, 1986). In large part, marine snow research geotechnical properties (Syvitski, 1991) and the ul- timate distribution of organic matter in continental Ł Corresponding author. Fax: C1 (619) 534-0784; E-mail: margin sediments (Ransom et al., 1997). Below we [email protected] present the results of a comparative study of the com- 0025-3227/98/$19.00 1998 Elsevier Science B.V. All rights reserved. PII S0025-3227(98)00052-8 40 B. Ransom et al. / Marine Geology 150 (1998) 39±50 ponents of marine snow from various water depths fabric and sediment chemical and physical properties offshore California. Our objectives were to identify across the California continental slope (Kim, 1996; the components and textures of aggregates traveling Ransom et al., 1997, 1998; Sawyer et al., 1997). in the nepheloid layer, improve our understanding Mendocino samples were retrieved from an anchored of how processes and conditions in the nepheloid array deployed for 64 days in ¾950 m of water with layer affect marine aggregates that originate in the collectors at water depths of 250, 750, and 930 m upper water column (pelagic zone), and examine the at 40ë1.990N, 124ë31.60W. San Luis Obispo samples possible impact these interactions may have on the were recovered from a ¯oating array deployed for 24 distribution of organic matter in the sediment. h at 35ë27.50N and 121ë31.00W. The ¯oating array Marine snow is a complex assemblage of or- had ®ve evenly spaced collectors at water depths ganisms, bioclasts (e.g., tests and frustules), organic from 50 to 250 m. matter, minerals, and fecal material entrained as dis- Trap depths were selected on the basis of trans- crete particles or small aggregates in a loose network missometer data which indicated that the water col- of exocellular muco-polysaccharide slime and ®brils umn in the sampling areas could be divided into (e.g., Alldredge, 1989; Decho, 1990; Heissenberger three zones. The surface layer, shown in representa- et al., 1996). The composition of marine snow is tive transmissometer traces in Fig. 2, coincides with a function of local particle abundance, particle en- the turbid photic zone which is characterized by high counter rates, and the ease with which different com- particle concentrations resulting from biological pro- ponents can be incorporated into larger aggregates. ductivity and sea-surface aggregation processes. The Through aggregation and disaggregation, as well as composition, size, and number of aggregates formed grazing by bacterial and planktonic heterotrophs, the in this layer are episodically affected by suspended architecture, particle composition and organic matter material from rivers during periods of heavy conti- in marine snow evolves through time (see review in nental runoff. The pelagic layer, a zone of reduced Wakehan and Lee, 1993). particle concentration, through which marine snow The direct observation of marine snow con- formed in the surface layer descends, occurs at the stituents and their textural relations requires use base of the surface layer and extends to the top of of a transmission electron microscope (TEM). To the nepheloid layer. The nepheloid layer stretches date, such studies have concentrated on fecal pel- from the sediment±water interface up to the base lets and=or aggregates generated in surface waters of the pelagic zone. This layer directly overlies the and pelagic regions of the water column (e.g., Silver sea ¯oor and experiences episodic turbidity from the and Bruland, 1981; Gowing and Silver, 1983, 1985; lateral transport and resuspension of detrital clastic Leppard et al., 1996). Only one study contains im- material as a result of oceanographic, sedimentolog- ages of nepheloid aggregates (Ransom et al., 1997). ical, and biological processes (e.g., bottom currents, The potential of this class of aggregates to in¯uence storms, sediment gravity ¯ows, slope failure, organ- sea ¯oor sediment microfabric and the distribution ism burrowing, etc.). To some extent, the boundaries and bioavailability of organic matter warrants further between the three layers shown in Fig. 2 are tem- investigation. porally and spatially variable, being dependent on water depth and prevailing biological, physical, and oceanographic conditions. 2. Sampling locations Marine snow samples were collected with Martin- 3. Methods Knauer multi-collector (eight tubes per water depth) sediment traps (Knauer et al., 1979) from transects Samples were collected and prepared to ensure that near Mendocino and San Luis Obispo on the Califor- aggregates represented the in-situ textures and parti- nia continental margin (Fig. 1) from June 13 to Au- cles present in the water column. Two of the eight col- gust 16, 1993. These samples form a companion data lectors at each water depth were used to obtain sam- set to a high-resolution study of the sediment micro- ples for TEM study; the six others were used for an B. Ransom et al. / Marine Geology 150 (1998) 39±50 41 Fig. 1. Location map of the Mendocino (northern) and San Luis Obispo (southern) locations sampled off the coast of California (see inset). Bathymetric contours are in meters. Sediment trap locations are indicated by crosses. investigation of organic carbon ¯ux and spiked with Prior to processing the carbon ¯ux material, formalin to kill planktonic scavengers. The TEM-des- planktonic scavengers were removed from the ®lter ignated collectors were ®lled with pH-buffered sea- papers so as not to affect the mass of organic carbon water containing 2 wt% glutaraldehyde. Sucrose was corresponding to that of the water column particles. added to these to increase solution density to ¾1.07 Filter papers were then dried and weighed to obtain gcm3 to minimize washout during trap recovery. the mass of marine aggregate material collected. The Upon retrieval, liquid in the upper three quarters of dried material was analyzed for total carbon using the TEM collectors was slowly siphoned off. All but a Perkin Elmer CHN analyzer (precision Dš0:3%, 50 ml of the remaining liquid was then slowly drained based on repeated measurements of a cystine stan- through the bottom of the collector. The resulting sus- dard) and inorganic carbon using acid-dissolution pension, which contained marine snow, was gently coulometry (precision Dš0:5%, based on repeated decanted into a jar spiked with glutaraldehyde and analysis of a carbonate standard). Organic carbon osmium tetroxide and refrigerated. In the carbon ¯ux was determined by difference. For further discus- collectors, ¯uid in each column was drained through sion of carbon analytical procedures and errors see the bottom and all entrained particulate matter was Ransom et al. (1998). deposited on a tared ®lter paper. In the laboratory, marine snow which was sus- 42 B. Ransom et al. / Marine Geology 150 (1998) 39±50 Fig. 2. Transmissometer plots from the Mendocino and San Luis Obispo sediment trap transects. The distinct gradient changes at the base of the surface and pelagic layers were used to distinguish boundaries between layers and shaded zones and indicate the relative extent of each layer. pended in the TEM-designated collectors was gently clastic particles (pieces of diatom frustules), clay separated with forceps into pieces 1±3 mm in di- minerals, organic matter, and microbes. Identi®ca- ameter in preparation for embedding. Aggregates tion of speci®c components carries a number of were then quickly ethanol-exchanged (¾10 min per caveats and the reliability of such determinations is ¯uid) and embedded in Spurr's resin (Hayat, 1970).
Load more

Recommended publications
  • Methane Cold Seeps As Biological Oases in the High‐
    LIMNOLOGY and Limnol. Oceanogr. 00, 2017, 00–00 VC 2017 The Authors Limnology and Oceanography published by Wiley Periodicals, Inc. OCEANOGRAPHY on behalf of Association for the Sciences of Limnology and Oceanography doi: 10.1002/lno.10732 Methane cold seeps as biological oases in the high-Arctic deep sea Emmelie K. L. A˚ strom€ ,1* Michael L. Carroll,1,2 William G. Ambrose, Jr.,1,2,3,4 Arunima Sen,1 Anna Silyakova,1 JoLynn Carroll1,2 1CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway 2Akvaplan-niva, FRAM – High North Research Centre for Climate and the Environment, Tromsø, Norway 3Division of Polar Programs, National Science Foundation, Arlington, Virginia 4Department of Biology, Bates College, Lewiston, Maine Abstract Cold seeps can support unique faunal communities via chemosynthetic interactions fueled by seabed emissions of hydrocarbons. Additionally, cold seeps can enhance habitat complexity at the deep seafloor through the accretion of methane derived authigenic carbonates (MDAC). We examined infaunal and mega- faunal community structure at high-Arctic cold seeps through analyses of benthic samples and seafloor pho- tographs from pockmarks exhibiting highly elevated methane concentrations in sediments and the water column at Vestnesa Ridge (VR), Svalbard (798 N). Infaunal biomass and abundance were five times higher, species richness was 2.5 times higher and diversity was 1.5 times higher at methane-rich Vestnesa compared to a nearby control region. Seabed photos reveal different faunal associations inside, at the edge, and outside Vestnesa pockmarks. Brittle stars were the most common megafauna occurring on the soft bottom plains out- side pockmarks.
    [Show full text]
  • Brochure.Pdf
    Two Little Fishies Two Little Fishies Inc. 4016 El Prado Blvd., Coconut Grove, Florida 33133 U.S.A. Tel (+01) 305 661.7742 Fax (+01) 305 661.0611 eMail: [email protected] ww w. t w o l i t t l e f i s h i e s . c o m © 2004 Two Little Fishies Inc. Two Little Fishies is a registered trademark of Two Little Fishies Inc.. All illustrations, photos and specifications contained in this broc h u r e are based on the latest pr oduct information available at the time of publication. Two Little Fishies Inc. res e r ves the right to make changes at any time, without notice. Printed in USA V.4 _ 2 0 0 4 Simple, Elegant, Practical,Solutions Useful... Two Little Fishies Two Little Fishies, Inc. was founded in 1991 to pr omote the reef aquarium hobby with its in t ro d u c t o r y video and books about ree f aquariums. The company now publishes and distributes the most popular reef aquarium ref e r ence books and identification guides in English, German French and Italian, under the d.b.a. Ricordea Publishing. Since its small beginning, Two Little Fishies has also grown to become a manufacturer and im p o r ter of the highest quality products for aquariums and water gardens, with interna t i o n a l distribution in the pet, aquaculture, and water ga r den industries. Two Little Fishies’ prod u c t line includes trace element supplements, calcium supplements and buffers, phosphate- fr ee activated carbon, granular iron - b a s e d phosphate adsorption media, underwa t e r bonding compounds, and specialty foods for fish and invertebrates.
    [Show full text]
  • Ch. 9: Ocean Biogeochemistry
    6/3/13 Ch. 9: Ocean Biogeochemistry NOAA photo gallery Overview • The Big Picture • Ocean Circulation • Seawater Composition • Marine NPP • Particle Flux: The Biological Pump • Carbon Cycling • Nutrient Cycling • Time Pemitting: Hydrothermal venting, Sulfur cycling, Sedimentary record, El Niño • Putting It All Together Slides borrowed from Aradhna Tripati 1 6/3/13 Ocean Circulation • Upper Ocean is wind-driven and well mixed • Surface Currents deflected towards the poles by land. • Coriolis force deflects currents away from the wind, forming mid-ocean gyres • Circulation moves heat poleward • River influx is to surface ocean • Atmospheric equilibrium is with surface ocean • Primary productivity is in the surface ocean Surface Currents 2 6/3/13 Deep Ocean Circulation • Deep and Surface Oceans separated by density gradient caused by differences in Temperature and Salinity • This drives thermohaline deep circulation: * Ice forms in the N. Atlantic and Southern Ocean, leaving behind cold, saline water which sinks * Oldest water is in N. Pacific * Distribution of dissolved gases and nutrients: N, P, CO2 Seawater Composition • Salinity is defined as grams of salt/kg seawater, or parts per thousand: %o • Major ions are in approximately constant concentrations everywhere in the oceans • Salts enter in river water, and are removed by porewater burial, sea spray and evaporites (Na, Cl). • Calcium and Sulfate are removed in biogenic sediments • Magnesium is consumed in hydrothermal vents, in ionic exchange for Ca in rock. • Potassium adsorbs in clays. 3 6/3/13 Major Ions in Seawater The Two-Box Model of the Ocean Precipitation Evaporation River Flow Upwelling Downwelling Particle Flux Sedimentation 4 6/3/13 Residence time vs.
    [Show full text]
  • Ocean Primary Production
    Learning Ocean Science through Ocean Exploration Section 6 Ocean Primary Production Photosynthesis very ecosystem requires an input of energy. The Esource varies with the system. In the majority of ocean ecosystems the source of energy is sunlight that drives photosynthesis done by micro- (phytoplankton) or macro- (seaweeds) algae, green plants, or photosynthetic blue-green or purple bacteria. These organisms produce ecosystem food that supports the food chain, hence they are referred to as primary producers. The balanced equation for photosynthesis that is correct, but seldom used, is 6CO2 + 12H2O = C6H12O6 + 6H2O + 6O2. Water appears on both sides of the equation because the water molecule is split, and new water molecules are made in the process. When the correct equation for photosynthe- sis is used, it is easier to see the similarities with chemo- synthesis in which water is also a product. Systems Lacking There are some ecosystems that depend on primary Primary Producers production from other ecosystems. Many streams have few primary producers and are dependent on the leaves from surrounding forests as a source of food that supports the stream food chain. Snow fields in the high mountains and sand dunes in the desert depend on food blown in from areas that support primary production. The oceans below the photic zone are a vast space, largely dependent on food from photosynthetic primary producers living in the sunlit waters above. Food sinks to the bottom in the form of dead organisms and bacteria. It is as small as marine snow—tiny clumps of bacteria and decomposing microalgae—and as large as an occasional bonanza—a dead whale.
    [Show full text]
  • Eukaryotic Microbes, Principally Fungi and Labyrinthulomycetes, Dominate Biomass on Bathypelagic Marine Snow
    The ISME Journal (2017) 11, 362–373 © 2017 International Society for Microbial Ecology All rights reserved 1751-7362/17 www.nature.com/ismej ORIGINAL ARTICLE Eukaryotic microbes, principally fungi and labyrinthulomycetes, dominate biomass on bathypelagic marine snow Alexander B Bochdansky1, Melissa A Clouse1 and Gerhard J Herndl2 1Ocean, Earth and Atmospheric Sciences, Old Dominion University, Norfolk, VA, USA and 2Department of Limnology and Bio-Oceanography, Division of Bio-Oceanography, University of Vienna, Vienna, Austria In the bathypelagic realm of the ocean, the role of marine snow as a carbon and energy source for the deep-sea biota and as a potential hotspot of microbial diversity and activity has not received adequate attention. Here, we collected bathypelagic marine snow by gentle gravity filtration of sea water onto 30 μm filters from ~ 1000 to 3900 m to investigate the relative distribution of eukaryotic microbes. Compared with sediment traps that select for fast-sinking particles, this method collects particles unbiased by settling velocity. While prokaryotes numerically exceeded eukaryotes on marine snow, eukaryotic microbes belonging to two very distant branches of the eukaryote tree, the fungi and the labyrinthulomycetes, dominated overall biomass. Being tolerant to cold temperature and high hydrostatic pressure, these saprotrophic organisms have the potential to significantly contribute to the degradation of organic matter in the deep sea. Our results demonstrate that the community composition on bathypelagic marine snow differs greatly from that in the ambient water leading to wide ecological niche separation between the two environments. The ISME Journal (2017) 11, 362–373; doi:10.1038/ismej.2016.113; published online 20 September 2016 Introduction or dense phytodetritus, but a large amount of transparent exopolymer particles (TEP, Alldredge Deep-sea life is greatly dependent on the particulate et al., 1993), which led us to conclude that they organic matter (POM) flux from the euphotic layer.
    [Show full text]
  • And Bathypelagic Fish Interactions with Seamounts and Mid-Ocean Ridges
    Meso- and bathypelagic fish interactions with seamounts and mid-ocean ridges Tracey T. Sutton1, Filipe M. Porteiro2, John K. Horne3 and Cairistiona I. H. Anderson3 1 Harbor Branch Oceanographic Institution, 5600 US Hwy. 1 N, Fort Pierce FL, 34946, USA (Current address: Virginia Institute of Marine Science, P.O.Box 1346, Gloucester Point, Virginia 23062-1346) 2 DOP, University of the Azores, Horta, Faial, the Azores 3 School of Aquatic and Fishery Sciences, University of Washington, Seattle WA, 98195, USA Contact e-mail (Sutton): [email protected]"[email protected] Tracey T. Sutton T. Tracey Abstract The World Ocean's midwaters contain the vast majority of Earth's vertebrates in the form of meso- and bathypelagic ('deep-pelagic,' in the combined sense) fishes. Understanding the ecology and variability of deep-pelagic ecosystems has increased substantially in the past few decades due to advances in sampling/observation technology. Researchers have discovered that the deep sea hosts a complex assemblage of organisms adapted to a “harsh” environment by terrestrial standards (i.e., dark, cold, high pressure). We have learned that despite the lack of physical barriers, the deep-sea realm is not a homogeneous ecosystem, but is spatially and temporally variable on multiple scales. While there is a well-documented reduction of biomass as a function of depth (and thus distance from the sun, ergo primary production) in the open ocean, recent surveys have shown that pelagic fish abundance and biomass can 'peak' deep in the water column in association with abrupt topographic features such as seamounts and mid-ocean ridges. We review the current knowledge on deep-pelagic fish interactions with these features, as well as effects of these interactions on ecosystem functioning.
    [Show full text]
  • Marine Snow Tracking Stereo Imaging System Junsu Jang
    Marine Snow Tracking Stereo Imaging System by Junsu Jang B.Sc., Carnegie Mellon University (2018) Submitted to the Program in Media Arts and Sciences, School of Architecture and Planning in partial fulfillment of the requirements for the degree of Master of Science in Media Arts and Sciences at the Massachusetts Institute of Technology September 2020 © Massachusetts Institute of Technology 2020. All rights reserved. Author.............................................................. Program in Media Arts and Sciences August 17th, 2020 Certified by. Joseph A. Paradiso Professor of Media Arts and Sciences Accepted by . Tod Machover Academic Head, Program in Media Arts and Sciences Marine Snow Tracking Stereo Imaging System by Junsu Jang Submitted to the Program in Media Arts and Sciences, School of Architecture and Planning on August 17th, 2020, in partial fulfillment of the requirements for the degree of Master of Science in Media Arts and Sciences Abstract The transport of particles of organic carbon from the ocean’s surface to its bottom plays a key role in the global carbon cycle and carbon sequestration. Quantifying the rate of this Biological Carbon Pump – the size and velocity distribution of falling particles below the mixing layer, for example – is thus of considerable importance. The complexity of this Pump, however, together with systematic biases in available measurement methodologies and vast spatial and temporal undersampling, makes this quantification difficult. In this thesis I set out to design and build a low-cost underwater stereo-imaging system to remotely measure the flux of sinking particles in the mid-ocean. By record- ing time-lapsed images of marine snow falling through the imaging volume over day- to-week timescales, we can estimate both the particle size distributions and, via 3D particle tracking velocimetry, their velocity distributions too.
    [Show full text]
  • Marine Snow, Zooplankton and Thin Layers: Indications of a Trophic Link from Small-Scale Sampling with the Video Plankton Recorder
    Vol. 468: 57–69, 2012 MARINE ECOLOGY PROGRESS SERIES Published November 14 doi: 10.3354/meps09984 Mar Ecol Prog Ser OPENPEN ACCESSCCESS Marine snow, zooplankton and thin layers: indications of a trophic link from small-scale sampling with the Video Plankton Recorder Klas O. Möller1,*, Michael St. John2,1, Axel Temming1, Jens Floeter1, Anne F. Sell3, Jens-Peter Herrmann1, Christian Möllmann1 1Institute for Hydrobiology and Fisheries Science, Center for Earth System Research and Sustainability (CEN), KlimaCampus, University of Hamburg, Grosse Elbstrasse 133, 22767 Hamburg, Germany 2National Institute of Aquatic Resources at the Technical University of Denmark, Charlottenlund Castle, 2920 Charlottenlund, Denmark 3Johann Heinrich von Thünen-Institut, Institute of Sea Fisheries, Palmaille 9, 22767 Hamburg, Germany ABSTRACT: Marine aggregates of biogenic origin, known as marine snow, are considered to play a major role in the ocean’s particle flux and may represent a concentrated food source for zoo- plankton. However, observing the marine snow−zooplankton interaction in the field is difficult since conventional net sampling does not collect marine snow quantitatively and cannot resolve so-called thin layers in which this interaction occurs. Hence, field evidence for the importance of the marine snow−zooplankton link is scarce. Here we employed a Video Plankton Recorder (VPR) to quantify small-scale (metres) vertical distribution patterns of fragile marine snow aggregates and zooplankton in the Baltic Sea during late spring 2002. By using this non-invasive optical sam- pling technique we recorded a peak in copepod abundance (ca. 18 ind. l−1) associated with a pro- nounced thin layer (50 to 55 m) of marine snow (maximum abundance of 28 particles l−1), a feature rarely resolved.
    [Show full text]
  • Zooplankton Fecal Pellets, Marine Snow and Sinking Phytoplankton Blooms
    AQUATIC MICROBIAL ECOLOGY Vol. 27: 57–102, 2002 Published February 18 Aquat Microb Ecol REVIEW Zooplankton fecal pellets, marine snow and sinking phytoplankton blooms Jefferson T. Turner* School for Marine Science and Technology, University of Massachusetts Dartmouth, 706 South Rodney French Boulevard, New Bedford, Massachusetts 02744-1221, USA ABSTRACT: Zooplankton fecal pellets have long been thought to be a dominant component of the sedimentary flux in marine and freshwater ecosystems, but that view is changing. The last 2 decades have seen publication of >500 studies using sediment traps, which reveal that zooplankton fecal pellets often constitute only a minor or variable proportion of the sedimentary flux. Substantial pro- portions of this flux are from organic aggregates (‘marine snow’) of various origins, including phyto- plankton blooms, which sediment directly to the benthos. It now appears that mainly large fecal pel- lets of macrozooplankton and fish are involved in the sedimentary flux. Smaller fecal pellets of microzooplankton and small mesozooplankton are mostly recycled or repackaged in the water column by microbial decomposition and coprophagy, contributing more to processes in the water column than flux to the benthos. The relative contributions of fecal pellets, marine snow and sinking phytoplankton to the vertical flux and recycling of materials in the water column are highly variable, dependent upon multiple interacting factors. These include variations in productivity, biomass, size spectra and composition of communities
    [Show full text]
  • Deep-Sea Research II 129 (2016) 4–19
    Deep-Sea Research II 129 (2016) 4–19 Contents lists available at ScienceDirect Deep-Sea Research II journal homepage: www.elsevier.com/locate/dsr2 The Gulf of Mexico ecosystem, six years after the Macondo oil well blowout Samantha B. Joye a,n, Annalisa Bracco b, Tamay M. Özgökmen c, Jeffrey P. Chanton d, Martin Grosell c, Ian R. MacDonald d, Erik E. Cordes e, Joseph P. Montoya f, Uta Passow g a Department of Marine Sciences, University of Georgia, Athens, GA 30602-3636, USA b School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA c Rosensteil School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA d Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA e Department of Biology, Temple University, Philadelphia, PA 19122, USA f College of Marine Sciences, University of South Florida, St. Petersburg, FL 33701, USA g Marine Science Institute, University of California, Santa Barbara, CA 93106, USA article info abstract Article history: The Gulf of Mexico ecosystem is a hotspot for biological diversity and supports a number of industries, Received 27 April 2016 from tourism to fishery production to oil and gas exploration, that serve as the economic backbone of Accepted 28 April 2016 Gulf coast states. The Gulf is a natural hydrocarbon basin, rich with stores of oil and gas that lie in Available online 12 May 2016 reservoirs deep beneath the seafloor. The natural seepage of hydrocarbons across the Gulf system is extensive and, thus, the system's biological components experience ephemeral, if not, frequent, hydro- carbon exposure.
    [Show full text]
  • Davidson Seamount Management Zone
    Monterey Bay National Marine Sanctuary Davidson Seamount Management Zone Management Plan Living Document June 2013 version 6.0 TABLE OF CONTENTS EXECUTIVE SUMMARY .......................................................................................................................................... 1 GOAL ............................................................................................................................................................................ 1 INTRODUCTION ........................................................................................................................................................ 1 CHARACTERISTICS OF SEAMOUNTS AND THE DAVIDSON SEAMOUNT MANAGEMENT ZONE ...................................... 1 NATIONAL SIGNIFICANCE OF DAVIDSON SEAMOUNT ................................................................................................. 3 POTENTIAL THREATS TO THE DAVIDSON SEAMOUNT ................................................................................................ 4 EXPANSION OF THE MBNMS TO INCLUDE DAVIDSON SEAMOUNT MANAGEMENT ZONE ......................................... 5 ACTION PLAN STATUS – STRATEGIES, ACTIVITIES, AND PARTNERS ................................................... 6 STRATEGY DS-1: CONDUCT SITE CHARACTERIZATION ............................................................................................. 6 STRATEGY DS-2: CONDUCT ECOLOGICAL PROCESSES INVESTIGATIONS ................................................................... 9 STRATEGY DS-3: DEVELOP
    [Show full text]
  • Nutrient Cycles in Marine Ecosystems
    Nutrient Cycles in Marine Ecosystems Chapter 4 Nitrogen, Carbon, Magnesium, Calcium, Phophorous Chapter 4 vocabulary 1. Nutrient 6. Assimilation 11.Leaching 2. Decomposer 7. Residence time 12.Marine snow 3. Reservoir 8. Sink 13.Dissociation 4. Run-off 9. Source 14.Diazotroph 5. Upwelling 10.Infiltration 15.Saprophytic Cycling of elements in the ecosystem Nutrient cycles move nutrients that are essential for life through the food chain through feeding. Nutrients: a chemical that provides what is needed for organisms to live and grow. When organisms die, decomposers break down the organic tissue and return it to inorganic forms. (inorganic forms could remain in ecosystem for millions of years before being synthesized into organic forms) Decomposer: bacteria and fungi that break down dead organic matter and release the nutrients back into the environment. The ocean is a reservoir for elements….. Reservoir: part of the abiotic phase of the nutrient cycle where nutrients can remain for long periods of time. Producers and microorganisms are able to fix inorganic molecules to organic substances. In this way… the abiotic part of the cycle can be moved into the biotic. (Fecal matter/dead organisms) Some are added to coral reefs and/or removed from the ocean altogether from harvesting. Molecules are added in through run-off and upwelling. Run-off: the flow of water from land caused by precipitation Upwelling: the movement of cold, nutrient rich water from deep in the ocean to the surface CONSUMERS BIOTIC PHASE PRIMARY DECOMPOSERS PRODUCERS ABIOTIC PHASE Nutrients found as inorganic ions and compounds in the atmosphere, dissolved in water, forming rocks and sediments Nutrient cycles Nutrients move from from the abiotic to the biotic when nutrients are absorbed and assimilated by producers Assimilation: the conversion of a nutrient into a usable form that can be incorporated into the tissues of an organism.
    [Show full text]