2.4 Evidence for Ocean Deoxygenation and Its Patterns: Eastern Boundary Upwelling Systems Francis Chan
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Virtual Population Analysis
1 INTRODUCTION 1.1 OVERVIEW There are a variety of VPA-type methods, which form powerful tools for stock assessment. At first sight, the large number of methods and their arcane names can put off the newcomer. However, this complexity is based on simple common components. All these methods use age-structured data to assess the state of a stock. The stock assessment is based on a population dynamics model, which defines how the age-structure changes through time. This model is the simplest possible description of numbers of similar aged fish where we wish to account for decreases in stock size through fishing activities. The diversity of VPA methods comes from the way they use different types of data and the way they are fitted. This manual is structured to describe the different components that make up a VPA stock assessment model: Population Model (Analytical Model) The population model is the common element among all VPA methods. The model defines the number of fish in a cohort based on the fishing history and age of the fish. A cohort is a set of fish all having (approximately) the same age, which gain no new members after recruitment, but decline through mortality. The fisheries model attempts to measure the impact catches have on the population. The population model usually will encapsulate the time series aspects of change and should include any random effects on the population (process errors), if any. Link Model Only rarely can variables in which we are interested be observed directly. Usually data consists of observations on variables that are only indirectly linked to variables of interest in the population model. -
Basic Concepts in Oceanography
Chapter 1 XA0101461 BASIC CONCEPTS IN OCEANOGRAPHY L.F. SMALL College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, United States of America Abstract Basic concepts in oceanography include major wind patterns that drive ocean currents, and the effects that the earth's rotation, positions of land masses, and temperature and salinity have on oceanic circulation and hence global distribution of radioactivity. Special attention is given to coastal and near-coastal processes such as upwelling, tidal effects, and small-scale processes, as radionuclide distributions are currently most associated with coastal regions. 1.1. INTRODUCTION Introductory information on ocean currents, on ocean and coastal processes, and on major systems that drive the ocean currents are important to an understanding of the temporal and spatial distributions of radionuclides in the world ocean. 1.2. GLOBAL PROCESSES 1.2.1 Global Wind Patterns and Ocean Currents The wind systems that drive aerosols and atmospheric radioactivity around the globe eventually deposit a lot of those materials in the oceans or in rivers. The winds also are largely responsible for driving the surface circulation of the world ocean, and thus help redistribute materials over the ocean's surface. The major wind systems are the Trade Winds in equatorial latitudes, and the Westerly Wind Systems that drive circulation in the north and south temperate and sub-polar regions (Fig. 1). It is no surprise that major circulations of surface currents have basically the same patterns as the winds that drive them (Fig. 2). Note that the Trade Wind System drives an Equatorial Current-Countercurrent system, for example. -
Fronts in the World Ocean's Large Marine Ecosystems. ICES CM 2007
- 1 - This paper can be freely cited without prior reference to the authors International Council ICES CM 2007/D:21 for the Exploration Theme Session D: Comparative Marine Ecosystem of the Sea (ICES) Structure and Function: Descriptors and Characteristics Fronts in the World Ocean’s Large Marine Ecosystems Igor M. Belkin and Peter C. Cornillon Abstract. Oceanic fronts shape marine ecosystems; therefore front mapping and characterization is one of the most important aspects of physical oceanography. Here we report on the first effort to map and describe all major fronts in the World Ocean’s Large Marine Ecosystems (LMEs). Apart from a geographical review, these fronts are classified according to their origin and physical mechanisms that maintain them. This first-ever zero-order pattern of the LME fronts is based on a unique global frontal data base assembled at the University of Rhode Island. Thermal fronts were automatically derived from 12 years (1985-1996) of twice-daily satellite 9-km resolution global AVHRR SST fields with the Cayula-Cornillon front detection algorithm. These frontal maps serve as guidance in using hydrographic data to explore subsurface thermohaline fronts, whose surface thermal signatures have been mapped from space. Our most recent study of chlorophyll fronts in the Northwest Atlantic from high-resolution 1-km data (Belkin and O’Reilly, 2007) revealed a close spatial association between chlorophyll fronts and SST fronts, suggesting causative links between these two types of fronts. Keywords: Fronts; Large Marine Ecosystems; World Ocean; sea surface temperature. Igor M. Belkin: Graduate School of Oceanography, University of Rhode Island, 215 South Ferry Road, Narragansett, Rhode Island 02882, USA [tel.: +1 401 874 6533, fax: +1 874 6728, email: [email protected]]. -
The Exchange of Water Between Prince William Sound and the Gulf of Alaska Recommended
The exchange of water between Prince William Sound and the Gulf of Alaska Item Type Thesis Authors Schmidt, George Michael Download date 27/09/2021 18:58:15 Link to Item http://hdl.handle.net/11122/5284 THE EXCHANGE OF WATER BETWEEN PRINCE WILLIAM SOUND AND THE GULF OF ALASKA RECOMMENDED: THE EXCHANGE OF WATER BETWEEN PRIMCE WILLIAM SOUND AND THE GULF OF ALASKA A THESIS Presented to the Faculty of the University of Alaska in partial fulfillment of the Requirements for the Degree of MASTER OF SCIENCE by George Michael Schmidt III, B.E.S. Fairbanks, Alaska May 197 7 ABSTRACT Prince William Sound is a complex fjord-type estuarine system bordering the northern Gulf of Alaska. This study is an analysis of exchange between Prince William Sound and the Gulf of Alaska. Warm, high salinity deep water appears outside the Sound during summer and early autumn. Exchange between this ocean water and fjord water is a combination of deep and intermediate advective intrusions plus deep diffusive mixing. Intermediate exchange appears to be an annual phen omenon occurring throughout the summer. During this season, medium scale parcels of ocean water centered on temperature and NO maxima appear in the intermediate depth fjord water. Deep advective exchange also occurs as a regular annual event through the late summer and early autumn. Deep diffusive exchange probably occurs throughout the year, being more evident during the winter in the absence of advective intrusions. ACKNOWLEDGMENTS Appreciation is extended to Dr. T. C. Royer, Dr. J. M. Colonell, Dr. R. T. Cooney, Dr. R. -
Hydrothermal Vents. Teacher's Notes
Hydrothermal Vents Hydrothermal Vents. Teacher’s notes. A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. They are usually volcanically active. Seawater penetrates into fissures of the volcanic bed and interacts with the hot, newly formed rock in the volcanic crust. This heated seawater (350-450°) dissolves large amounts of minerals. The resulting acidic solution, containing metals (Fe, Mn, Zn, Cu) and large amounts of reduced sulfur and compounds such as sulfides and H2S, percolates up through the sea floor where it mixes with the cold surrounding ocean water (2-4°) forming mineral deposits and different types of vents. In the resulting temperature gradient, these minerals provide a source of energy and nutrients to chemoautotrophic organisms that are, thus, able to live in these extreme conditions. This is an extreme environment with high pressure, steep temperature gradients, and high concentrations of toxic elements such as sulfides and heavy metals. Black and white smokers Some hydrothermal vents form a chimney like structure that can be as 60m tall. They are formed when the minerals that are dissolved in the fluid precipitates out when the super-heated water comes into contact with the freezing seawater. The minerals become particles with high sulphur content that form the stack. Black smokers are very acidic typically with a ph. of 2 (around that of vinegar). A black smoker is a type of vent found at depths typically below 3000m that emit a cloud or black material high in sulphates. White smokers are formed in a similar way but they emit lighter-hued minerals, for example barium, calcium and silicon. -
Introduction to Co2 Chemistry in Sea Water
INTRODUCTION TO CO2 CHEMISTRY IN SEA WATER Andrew G. Dickson Scripps Institution of Oceanography, UC San Diego Mauna Loa Observatory, Hawaii Monthly Average Carbon Dioxide Concentration Data from Scripps CO Program Last updated August 2016 2 ? 410 400 390 380 370 2008; ~385 ppm 360 350 Concentration (ppm) 2 340 CO 330 1974; ~330 ppm 320 310 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Year EFFECT OF ADDING CO2 TO SEA WATER 2− − CO2 + CO3 +H2O ! 2HCO3 O C O CO2 1. Dissolves in the ocean increase in decreases increases dissolved CO2 carbonate bicarbonate − HCO3 H O O also hydrogen ion concentration increases C H H 2. Reacts with water O O + H2O to form bicarbonate ion i.e., pH = –lg [H ] decreases H+ and hydrogen ion − HCO3 and saturation state of calcium carbonate decreases H+ 2− O O CO + 2− 3 3. Nearly all of that hydrogen [Ca ][CO ] C C H saturation Ω = 3 O O ion reacts with carbonate O O state K ion to form more bicarbonate sp (a measure of how “easy” it is to form a shell) M u l t i p l e o b s e r v e d indicators of a changing global carbon cycle: (a) atmospheric concentrations of carbon dioxide (CO2) from Mauna Loa (19°32´N, 155°34´W – red) and South Pole (89°59´S, 24°48´W – black) since 1958; (b) partial pressure of dissolved CO2 at the ocean surface (blue curves) and in situ pH (green curves), a measure of the acidity of ocean water. -
Hypoxia Infographic
Understanding HYP XIA Hypoxia is an environmental phenomenon where the concentration of dissolved oxygen in the water column decreases to a level that can no longer 1 support living aquatic organisms. The level is often considered to be 2 mg O2 per liter of water or lower. Hypoxic and anoxic (no oxygen) waters have existed throughout geologic time, but their occurrence in shallow coastal and estuarine areas appears to be increasing as a result of human activities. 2 What causes hypoxia? In 2015, scientists determined the Gulf of Mexico dead zone to be 6,474 square miles, which is an area about the size of Connecticut and Rhode Island combined. 3 Major events leading to the formation of hypoxia in the Gulf of Mexico include: Coastal Hypoxia and Eutrophication Sunlight Watershed Areas of anthropogenically-influenced n> In the past century, Hypoxia has become a global concern with estuarine and coastal hypoxia. 550 over 550 coastal areas identified as experiencing this issue. 4 Runoff and nutrient 1 loading of the Mississippi River. Nutrient-rich water from the Mississippi River forms 1960 a surface lens. 1970 Combined, Dead Zones 1980 cover 4x the area of the 1990 Great Lakes. % 2000 Nutrient-enhanced 4 2 primary production, Only a small fraction of the 550-plus Number of dead zones has approximately Today, there is currently about 1,148,000 km2 or eutrophication. hypoxia zones exhibited any signs doubled each decade since the 1960’s. 5 of seabed covered by Oxygen Minimum Phytoplankton growth of improvement. 5 Zones (OMZs) (<0.5 ml of O /liter) 5 is fueled by nutrients. -
Gulf of Mexico Hypoxia Monitoring Strategy
Gulf of Mexico Hypoxia Monitoring Strategy Hypoxia Zone Areal Extent (km2) Interpolation Observations Data Analysis Workshop Steering Committee Trevor Meckley, Alan Lewitus, A White Paper by the Steering Committee of the: Dave Scheurer, Dave Hilmer NOAA National Ocean Service, National 6th Annual NOAA/NGI Hypoxia Research Centers of Coastal Ocean Science Coordination Workshop: Establishing a Steve Ashby Cooperative Hypoxic Zone Monitoring Program Northern Gulf Institute convened by the NOAA National Centers for Steve DiMarco Texas A&M University Coastal Ocean Science and Northern Gulf Institute Steve Giordano on 12-13 September 2016 at the Mississippi State NOAA National Marine Fisheries Service University Science and Technology Center at Rick Greene NASA's Stennis Space Center in Mississippi. EPA Office of Research and Development Stephan Howden University of Southern Mississippi Barb Kirkpatrick Gulf of Mexico Coastal Ocean Observing System Troy Pierce EPA Gulf of Mexico Program Nancy Rabalais Louisiana Universities Marine Consortium Rick Raynie Louisiana Coastal Protection and Restoration Authority Mike Woodside USGS National Water Quality Program Abstract The Gulf of Mexico Hypoxia Monitoring Strategy is a resource to inform the proceedings of the 6th Annual NOAA/NGI Hypoxia Research Coordination Workshop: Establishing a Cooperative Hypoxic Zone Monitoring Program. It provides a framework for a cooperative hypoxia monitoring program based on programmatic and financial requirements that are designed to meet management needs. The Monitoring Strategy includes sections on management drivers, current monitoring capabilities and gaps, and projected programmatic, data, and financial requirements based on the input of multiple partners and the responses from a survey of modelers currently applying deterministic 3D time variable models to Gulf hypoxia assessment and prediction. -
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. -
Issues Brief: Ocean Deoxygenation
DECEMBER 2019 OCEAN DEOXYGENATION • The oxygen content of the ocean has declined by around 2% since the middle of the 20th century overall, while the volume of ocean waters completely depleted of oxygen has quadrupled since the 1960s. • Ocean oxygen levels are expected to fall on average by 3–4% by 2100 overall due to climate change and increased nutrient discharges, though the scale of effect seen will vary regionally. • Consequences of ocean oxygen decline include decreased biodiversity, shifts in species distributions, displacement or reduction in fishery resources and expanding algal blooms. • Ocean deoxygenation threatens to disrupt the ocean’s food provisioning ecosystem services. • To slow and reverse the loss of oxygen, humans must urgently mitigate climate change globally and nutrient pollution locally. What is the issue? conditions. In 2011 there were around 700 reported sites worldwide affected by low oxygen conditions – Globally, oceans have lost around 2% of dissolved up from only 45 before the 1960s. The volume of oxygen since the 1950s and are expected to lose anoxic ocean waters – areas completely depleted of about 3–4% by the year 2100 under a business-as- oxygen – has quadrupled since the 1960s. Evidence usual scenario (Representative Concentration suggests that temperature increases explain about Pathway 8.5), though the scale of effect is predicted 50% of oxygen loss in the upper 1000 m of the to vary regionally. Much of the oxygen loss is ocean. concentrated in the upper 1000m where species richness and abundance is highest. Even slight overall reductions in the levels of oxygen dissolved in the oceans can induce oxygen stress in marine organisms by depriving them of an adequate oxygen supply at the tissue level (termed hypoxia). -
The Global Marine Phosphorus Cycle: Sensitivity to Oceanic Circulation
Biogeosciences, 4, 155–171, 2007 www.biogeosciences.net/4/155/2007/ Biogeosciences © Author(s) 2007. This work is licensed under a Creative Commons License. The global marine phosphorus cycle: sensitivity to oceanic circulation C. P. Slomp and P. Van Cappellen Department of Earth Sciences – Geochemistry, Faculty of Geosciences, Utrecht University, P.O. Box 80021, 3508 TA Utrecht, The Netherlands Received: 4 September 2006 – Published in Biogeosciences Discuss.: 5 October 2006 Revised: 8 January 2007 – Accepted: 20 February 2007 – Published: 22 February 2007 Abstract. A new mass balance model for the coupled ma- stand long-term variations in marine biological activity, at- rine cycles of phosphorus (P) and carbon (C) is used to ex- mospheric composition and climate (Holland, 1984; Van amine the relationships between oceanic circulation, primary Cappellen and Ingall, 1996; Petsch and Berner, 1998; Bjer- productivity, and sedimentary burial of reactive P and partic- rum and Canfield, 2002). Important forcings include the sup- ulate organic C (POC), on geological time scales. The model ply of reactive P from the continents, oceanic circulation and explicitly represents the exchanges of water and particulate sea level fluctuations (Follmi,¨ 1996; Compton et al., 2000; matter between the continental shelves and the open ocean, Handoh and Lenton, 2003; Wallmann, 2003; Bjerrum et al., and it accounts for the redox-dependent burial of POC and 2006). the various forms of reactive P (iron(III)-bound P, particu- Upward transport of nutrient-rich water sustains biologi- late organic P (POP), authigenic calcium phosphate, and fish cal activity in marine surface waters. Vertical mixing, how- debris). Steady state and transient simulations indicate that ever, also controls the ventilation of the deeper ocean waters, a slowing down of global ocean circulation decreases pri- which in turn has a major effect on the sedimentary burial mary production in the open ocean, but increases that in the of phosphorus. -
EXPLORING DEEP SEA HYDROTHERMAL VENTS on EARTH and OCEAN WORLDS. P. Sobron1,2, L. M. Barge3, the Invader Team. 1Impossible Sensing, St
52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548) 2505.pdf EXPLORING DEEP SEA HYDROTHERMAL VENTS ON EARTH AND OCEAN WORLDS. P. Sobron1,2, L. M. Barge3, the InVADER Team. 1Impossible Sensing, St. Louis, MO ([email protected]) 2SETI Institute, Mtn. View, CA, , 3Jet Propulsion Laboratory, Pasadena, CA The Mission: InVADER (In-situ Vent Analysis precipitates showing exposed minerals and organic Divebot for Exobiology Research, Figure 4.1, content. The UNOLS ROV will use our coring tool and https://invader-mission.org/) is NASA’s most advanced its own manipulator and cameras to take ground truth subsea sensing payload, a tightly integrated imaging and samples as part of the InVADER deplotment. laser Raman spectroscopy/laser-induced breakdown In contrast to existing methods, InVADER allows spectroscopy/laser induced native fluorescence in-situ, autonomous, non-destructive measurements of instrument capable of in-situ, rapid, long-term these vent characteristics. InVADER will fill these gaps, underwater analyses of vent fluid and precipitates. and advance readiness in vent exploration on Earth and Such analyses are critical for finding and studying Ocean Worlds by simplifying operational strategies for life and life’s precursors at vent systems on Ocean identifying and characterizing seafloor environments. Worlds. To demonstrate the scientific potential and We will use statistical analysis tools for the fusion of functionality of the instrument, in July 2021 our team multi-sensor datasets, and develop real-time science will deploy InVADER on the Ocean Observatories data evaluation and payload control routines to Initiative’s (OOI) Regional Cabled Array (RCA), a establish, and then validate, adaptive science operations power/data distribution network off the Oregon coast, at strategies that maximize science return in a mission-like the underwater hydrothermal systems of Axial scenario.