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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. -
7.014 Handout PRODUCTIVITY: the “METABOLISM” of ECOSYSTEMS
7.014 Handout PRODUCTIVITY: THE “METABOLISM” OF ECOSYSTEMS Ecologists use the term “productivity” to refer to the process through which an assemblage of organisms (e.g. a trophic level or ecosystem assimilates carbon. Primary producers (autotrophs) do this through photosynthesis; Secondary producers (heterotrophs) do it through the assimilation of the organic carbon in their food. Remember that all organic carbon in the food web is ultimately derived from primary production. DEFINITIONS Primary Productivity: Rate of conversion of CO2 to organic carbon (photosynthesis) per unit surface area of the earth, expressed either in terns of weight of carbon, or the equivalent calories e.g., g C m-2 year-1 Kcal m-2 year-1 Primary Production: Same as primary productivity, but usually expressed for a whole ecosystem e.g., tons year-1 for a lake, cornfield, forest, etc. NET vs. GROSS: For plants: Some of the organic carbon generated in plants through photosynthesis (using solar energy) is oxidized back to CO2 (releasing energy) through the respiration of the plants – RA. Gross Primary Production: (GPP) = Total amount of CO2 reduced to organic carbon by the plants per unit time Autotrophic Respiration: (RA) = Total amount of organic carbon that is respired (oxidized to CO2) by plants per unit time Net Primary Production (NPP) = GPP – RA The amount of organic carbon produced by plants that is not consumed by their own respiration. It is the increase in the plant biomass in the absence of herbivores. For an entire ecosystem: Some of the NPP of the plants is consumed (and respired) by herbivores and decomposers and oxidized back to CO2 (RH). -
Cold Seep Benthic Communities in Japan Subduction Zones: Spatial Organization, Trophic Strategies and Evidence for Temporal Evolution*
MARINE ECOLOGY - PROGRESS SERIES Vol. 40: 115-126. 1987 Published October 7 Mar. Ecol. Prog. Ser. Cold seep benthic communities in Japan subduction zones: spatial organization, trophic strategies and evidence for temporal evolution* S. Kim Juniper", Myriam Sibuet IFREMER, Centre de Brest. BP 337. F-29273 Brest Cedex. France ABSTRACT: Submersible exploration of the Japan subduction zones has revealed benthic communities dominated by clams (Calyptogena spp.) around sed~mentporewater seeps at depths from 3850 to 6000 m. Photographic and video records were used to produce microcartographlc reconstructions of 3 contrasting cold seep sites. Spatial and abundance relations of megafauna lead us to propose several hypotheses regard~ngthe ecological functioning of these cold seep communities. We dlst~nguish between the likely direct use of reducing substances in venting fluids by Calyptogena-bacteria symbioses and indirect usage by accompanying abyssal species not known to harbour symbionts. Microdistribution and known or presumed feedmg modes of the accompanying species indicate 2 different sources of organic matter enrichment within cold seep sites: organic debris originating from bivalve colonies, and enrichment of extensive areas of surrounding surface sediments where weaker, more hffuse porewater seepage may support chemosynthetic production by free-living bacteria. The occurrence of colony-like groupings of empty Calyptogena valves indicates that cold seeps are ephemeral, with groups of living clams, mixed living and dead clams, and empty dissolving shells marlung the course of a cycle of porewater venting and offering clues to the recent history of cold seep activity. INTRODUCTION al. 1985). One of the bivalve species from this area has been shown to harbour symbiotic bacteria in its gill The discovery of deep-sea hydrothermal vents has tissue and to oxidise methane (Childress et al. -
Coastal and Marine Ecological Classification Standard (2012)
FGDC-STD-018-2012 Coastal and Marine Ecological Classification Standard Marine and Coastal Spatial Data Subcommittee Federal Geographic Data Committee June, 2012 Federal Geographic Data Committee FGDC-STD-018-2012 Coastal and Marine Ecological Classification Standard, June 2012 ______________________________________________________________________________________ CONTENTS PAGE 1. Introduction ..................................................................................................................... 1 1.1 Objectives ................................................................................................................ 1 1.2 Need ......................................................................................................................... 2 1.3 Scope ........................................................................................................................ 2 1.4 Application ............................................................................................................... 3 1.5 Relationship to Previous FGDC Standards .............................................................. 4 1.6 Development Procedures ......................................................................................... 5 1.7 Guiding Principles ................................................................................................... 7 1.7.1 Build a Scientifically Sound Ecological Classification .................................... 7 1.7.2 Meet the Needs of a Wide Range of Users ...................................................... -
Grade 3 Unit 2 Overview Open Ocean Habitats Introduction
G3 U2 OVR GRADE 3 UNIT 2 OVERVIEW Open Ocean Habitats Introduction The open ocean has always played a vital role in the culture, subsistence, and economic well-being of Hawai‘i’s inhabitants. The Hawaiian Islands lie in the Pacifi c Ocean, a body of water covering more than one-third of the Earth’s surface. In the following four lessons, students learn about open ocean habitats, from the ocean’s lighter surface to the darker bottom fl oor thousands of feet below the surface. Although organisms are scarce in the deep sea, there is a large diversity of organisms in addition to bottom fi sh such as polycheate worms, crustaceans, and bivalve mollusks. They come to realize that few things in the open ocean have adapted to cope with the increased pressure from the weight of the water column at that depth, in complete darkness and frigid temperatures. Students fi nd out, through instruction, presentations, and website research, that the vast open ocean is divided into zones. The pelagic zone consists of the open ocean habitat that begins at the edge of the continental shelf and extends from the surface to the ocean bottom. This zone is further sub-divided into the photic (sunlight) and disphotic (twilight) zones where most ocean organisms live. Below these two sub-zones is the aphotic (darkness) zone. In this unit, students learn about each of the ocean zones, and identify and note animals living in each zone. They also research and keep records of the evolutionary physical features and functions that animals they study have acquired to survive in harsh open ocean habitats. -
World Ocean Thermocline Weakening and Isothermal Layer Warming
applied sciences Article World Ocean Thermocline Weakening and Isothermal Layer Warming Peter C. Chu * and Chenwu Fan Naval Ocean Analysis and Prediction Laboratory, Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-831-656-3688 Received: 30 September 2020; Accepted: 13 November 2020; Published: 19 November 2020 Abstract: This paper identifies world thermocline weakening and provides an improved estimate of upper ocean warming through replacement of the upper layer with the fixed depth range by the isothermal layer, because the upper ocean isothermal layer (as a whole) exchanges heat with the atmosphere and the deep layer. Thermocline gradient, heat flux across the air–ocean interface, and horizontal heat advection determine the heat stored in the isothermal layer. Among the three processes, the effect of the thermocline gradient clearly shows up when we use the isothermal layer heat content, but it is otherwise when we use the heat content with the fixed depth ranges such as 0–300 m, 0–400 m, 0–700 m, 0–750 m, and 0–2000 m. A strong thermocline gradient exhibits the downward heat transfer from the isothermal layer (non-polar regions), makes the isothermal layer thin, and causes less heat to be stored in it. On the other hand, a weak thermocline gradient makes the isothermal layer thick, and causes more heat to be stored in it. In addition, the uncertainty in estimating upper ocean heat content and warming trends using uncertain fixed depth ranges (0–300 m, 0–400 m, 0–700 m, 0–750 m, or 0–2000 m) will be eliminated by using the isothermal layer. -
Deep-Sea Mining: the Basics
A fact sheet from June 2018 NOAA Office of Ocean Exploration and Research Deep-sea Mining: The Basics Overview The deepest parts of the world’s ocean feature ecosystems found nowhere else on Earth. They provide habitat for multitudes of species, many yet to be named. These vast, lightless regions also possess deposits of valuable minerals in rich concentrations. Deep-sea extraction technologies may soon develop to the point where exploration of seabed minerals can give way to active exploitation. The International Seabed Authority (ISA) is charged with formulating and enforcing rules for all seabed mining that takes place in waters beyond national jurisdictions. These rules are now under development. Environmental regulations, liability and financial rules, and oversight and enforcement protocols all must be written and approved within three to five years. Figure 1 Types of Deep-sea Mining Production support vessel Return pipe Riser pipe Cobalt Seafloor massive Polymetallic crusts sulfides nodules Subsurface plumes 800-2,500 from return water meters deep Deposition 1,000-4,000 meters deep 4,000-6,500 meters deep Cobalt-rich Localized plumes Seabed pump Ferromanganeseferromanganese from cutting crusts Seafloor production tool Nodule deposit Massive sulfide deposit Sediment Source: New Zealand Environment Guide © 2018 The Pew Charitable Trusts 2 The legal foundations • The United Nations Convention on the Law of the Sea (UNCLOS). Also known as the Law of the Sea Treaty, UNCLOS is the constitutional document governing mineral exploitation on the roughly 60 percent of the world seabed that lies beyond national jurisdictions. UNCLOS took effect in 1994 upon passage of key enabling amendments designed to spur commercial mining. -
Relationships Between Net Primary Production, Water Transparency, Chlorophyll A, and Total Phosphorus in Oak Lake, Brookings County, South Dakota
Proceedings of the South Dakota Academy of Science, Vol. 92 (2013) 67 RELATIONSHIPS BETWEEN NET PRIMARY PRODUCTION, WATER TRANSPARENCY, CHLOROPHYLL A, AND TOTAL PHOSPHORUS IN OAK LAKE, BROOKINGS COUNTY, SOUTH DAKOTA Lyntausha C. Kuehl and Nels H. Troelstrup, Jr.* Department of Natural Resource Management South Dakota State University Brookings, SD 57007 *Corresponding author email: [email protected] ABSTRACT Lake trophic state is of primary concern for water resource managers and is used as a measure of water quality and classification for beneficial uses. Secchi transparency, total phosphorus and chlorophyll a are surrogate measurements used in the calculation of trophic state indices (TSI) which classify waters as oligotrophic, mesotrophic, eutrophic or hypereutrophic. Yet the relationships between these surrogate measurements and direct measures of lake productivity vary regionally and may be influenced by external factors such as non-algal tur- bidity. Prairie pothole basins, common throughout eastern South Dakota and southwestern Minnesota, are shallow glacial lakes subject to frequent winds and sediment resuspension. Light-dark oxygen bottle methodology was employed to evaluate vertical planktonic production within an eastern South Dakota pothole basin. Secchi transparency, total phosphorus and planktonic chlorophyll a were also measured from each of three basin sites at biweekly intervals throughout the 2012 growing season. Secchi transparencies ranged between 0.13 and 0.25 meters, corresponding to an average TSISD value of 84.4 (hypereutrophy). Total phosphorus concentrations ranged between 178 and 858 ug/L, corresponding to an average TSITP of 86.7 (hypereutrophy). Chlorophyll a values corresponded to an average TSIChla value of 69.4 (transitional between eutrophy and hypereutro- phy) and vertical production profiles yielded areal net primary productivity val- ues averaging 288.3 mg C∙m-2∙d-1 (mesotrophy). -
Seabed Mapping: a Brief History from Meaningful Words
geosciences Review Seabed Mapping: A Brief History from Meaningful Words Pedro Smith Menandro and Alex Cardoso Bastos * Marine Geosciences Lab (Labogeo), Departmento Oceanografia, Universidade Federal do Espírito Santo, Vitória-ES 29075-910, Brazil; [email protected] * Correspondence: [email protected] Received: 19 May 2020; Accepted: 7 July 2020; Published: 16 July 2020 Abstract: Over the last few centuries, mapping the ocean seabed has been a major challenge for marine geoscientists. Knowledge of seabed bathymetry and morphology has significantly impacted our understanding of our planet dynamics. The history and scientific trends of seabed mapping can be assessed by data mining prior studies. Here, we have mined the scientific literature using the keyword “seabed mapping” to investigate and provide the evolution of mapping methods and emphasize the main trends and challenges over the last 90 years. An increase in related scientific production was observed in the beginning of the 1970s, together with an increased interest in new mapping technologies. The last two decades have revealed major shift in ocean mapping. Besides the range of applications for seabed mapping, terms like habitat mapping and concepts of seabed classification and backscatter began to appear. This follows the trend of investments in research, science, and technology but is mainly related to national and international demands regarding defining that country’s exclusive economic zone, the interest in marine mineral and renewable energy resources, the need for spatial planning, and the scientific challenge of understanding climate variability. The future of seabed mapping brings high expectations, considering that this is one of the main research and development themes for the United Nations Decade of the Oceans. -
Skagerrak Interconnecting Grids, Upgrade
Skagerrak Interconnecting grids, Upgrade An excellent example of the benefits that can be achieved through interconnections. The Skagerrak HVDC transmission system comprises several The system will help overcome distance and grid constraints HVDC links which together provide a total of 1,640 MW trans- while ensuring robust performance, power quality and minimal mission capacity between Kristiansand in southern Norway electrical losses. In the rare case of a power system outage, and Tjele on Denmark’s Jutland peninsula. The link is owned the technology’s ‘black-start’ capability allows for a fast net- by Statnett in Norway, and Energinet.dk in Denmark. work restoration using power from the other end of the link. These factors were essential in the selection of the HVDC Light Skagerrak 1&2 rated 500 MW was commissioned in 1976-77 technology for the fourth Skagerrak HVDC link. and Skagerrak 3, rated 440 MW, became operational in 1993. The latest Skagerrak project was awarded to ABB in 2011, and comprises a fourth link using HVDC Light technology which will operate in a bipole mode together with the Skager- rak 3 HVDC Classic link and a control system upgrade of the latter. This is the first time an HVDC Classic and an HVDC Light link will be tied together in such a bipole configuration. This is possible because of ABB’s advanced MACH control system, which was also used for a Skagerrak 1-2 upgrade in 2007. The new link will boost transmission capacity between the mainly hydroelectric-based Norwegian system and the wind and thermal power-based Danish system by an additional 700 MW with a voltage rating of 500 kV. -
Productivity Is Defined As the Ratio of Output to Input(S)
Institute for Development Policy and Management (IDPM) Development Economics and Public Policy Working Paper Series WP No. 31/2011 Published by: Development Economics and Public Policy Cluster, Institute of Development Policy and Management, School of Environment and Development, University of Manchester, Manchester M13 9PL, UK; email: [email protected]. PRODUCTIVITY MEASUREMENT IN INDIAN MANUFACTURING: A COMPARISON OF ALTERNATIVE METHODS Vinish Kathuria SJMSOM, Indian Institute of Technology Bombay [email protected] Rajesh S N Raj * Centre for Multi-Disciplinary Development Research, Dharwad [email protected] Kunal Sen IDPM, University of Manchester [email protected] Abstract Very few other issues in explaining economic growth has generated so much debate than the measurement of total factor productivity (TFP) growth. The concept of TFP and its measurement and interpretation have offered a fertile ground for researchers for more than half a century. This paper attempts to provide a review of different issues in the measurement of TFP including the choice of inputs and outputs. The paper then gives a brief review of different techniques used to compute TFP growth. Using three different techniques – growth accounting (non-parametric), production function accounting for endogeniety (semi-parametric) and stochastic production frontier (parametric) – the paper computes the TFP growth of Indian manufacturing for both formal and informal sectors from 1989-90 to 2005-06. The results indicate that the TFP growth of formal and informal sector has differed greatly during this 16-year period but that the estimates are sensitive to the technique used. This suggests that any inference on productivity growth in India since the economic reforms of 1991 is conditional on the method of measurement used, and that there is no unambiguous picture emerging on the direction of change in TFP growth in post-reform India. -
Structure and Distribution of Cold Seep Communities Along the Peruvian Active Margin: Relationship to Geological and Fluid Patterns
MARINE ECOLOGY PROGRESS SERIES Vol. 132: 109-125, 1996 Published February 29 Mar Ecol Prog Ser l Structure and distribution of cold seep communities along the Peruvian active margin: relationship to geological and fluid patterns 'Laboratoire Ecologie Abyssale, DROIEP, IFREMER Centre de Brest, BP 70, F-29280 Plouzane, France '~epartementdes Sciences de la Terre, UBO, 6 ave. Le Gorgeu, F-29287 Brest cedex, France 3~aboratoireEnvironnements Sedimentaires, DROIGM, IFREMER Centre de Brest, BP 70, F-29280 Plouzane, France "niversite P. et M. Curie, Observatoire Oceanologique de Banyuls, F-66650 Banyuls-sur-Mer, France ABSTRACT Exploration of the northern Peruvian subduction zone with the French submersible 'Nau- tile' has revealed benthlc communities dominated by new species of vesicomyid bivalves (Calyptogena spp and Ves~comyasp ) sustained by methane-nch fluid expulsion all along the continental margin, between depths of 5140 and 2630 m Videoscoplc studies of 25 dives ('Nautiperc cruise 1991) allowed us to describe the distribution of these biological conlnlunities at different spahal scales At large scale the communities are associated with fluid expuls~onalong the major tectonic features (scarps, canyons) of the margln At a smaller scale on the scarps, the distribuhon of the communities appears to be con- trolled by fluid expulsion along local fracturatlon features such as joints, faults and small-scale scars Elght dlves were made at one particular geological structure the Middle Slope Scarp (the scar of a large debns avalanche) where numerous