Seafloor Hydrothermal Systems I. Introduction the Mid-Ocean Ridge
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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. -
Hydrothermal Circulation Within the Endeavour Segment; Juan De Fuca Ridge
Hydrothermal Circulation within the Endeavour Segment; Juan de Fuca Ridge H. Paul Johnson1, Maurice A. Tivey2, Tor A. Bjorklund1, and Marie S. Salmi1 1School of Oceanography, University of Washington, Seattle, WA 98195-7940 2Department of Geology and Geophysics Woods Hole Oceanographic Institution Woods Hole, MA 02543 Correspondence should be addressed to HPJ, [email protected] 206-543-8474 Hydrothermal Circulation within the Endeavour Segment; Juan de Fuca Ridge Abstract Areas of the seafloor at mid-ocean ridges where hydrothermal vents discharge are easily recognized by the dramatic biological, physical and chemical processes that characterize such sites. Locations where seawater flows into the seafloor to recharge hydrothermal cells within the crustal reservoir are by contrast almost invisible, but can be indirectly identified by a systematic grid of conductive heat flow measurements. An array of conductive heat flow stations in the Endeavour axial valley of the Juan de Fuca Ridge has identified recharge zones that appear to represent a nested system of fluid circulation paths. At the scale of an axial rift valley, conductive heat flow data indicate a general cross-valley fluid flow, where seawater enters the shallow sub-surface crustal reservoir at the eastern wall of the Endeavour axial valley and undergoes a kilometer of horizontal transit beneath the valley floor, finally exiting as warm hydrothermal fluid discharge on the western valley bounding wall. Recharge zones also have been identified as located within an annular ring of very cold seafloor around the large Main Endeavour Hydrothermal Field, with seawater inflow occurring within faults that surround the fluid discharge sites. -
Three-Dimensional Models of Hydrothermal Circulation Through a Seamount Network on Fast-Spreading Crust ∗ Rachel M
Earth and Planetary Science Letters 501 (2018) 138–151 Contents lists available at ScienceDirect Earth and Planetary Science Letters www.elsevier.com/locate/epsl Three-dimensional models of hydrothermal circulation through a seamount network on fast-spreading crust ∗ Rachel M. Lauer a,b,c, , Andrew T. Fisher b,c, Dustin M. Winslow b,c,d a Department of Geoscience, University of Calgary, Calgary, Alberta, Canada b Earth and Planetary Sciences Department, University of California, Santa Cruz, 95064, USA c Center for Dark Energy Biosphere Investigations, University of California, Santa Cruz, 95064, USA d GrowthIntel, 25-27 Horsell Road, London N5 1XL, UK a r t i c l e i n f o a b s t r a c t Article history: We present results from three-dimensional, transient, fully coupled simulations of fluid and heat Received 25 February 2018 transport on a ridge flank in fast-spread ocean crust. The simulations quantify relationships between rates Received in revised form 17 July 2018 of fluid flow, the extent of advective heat extraction, the geometry of crustal aquifers and outcrops, and Accepted 14 August 2018 crustal hydrologic parameters, with the goal of simulating conditions similar to those seen on 18–24 M.y. Available online xxxx old seafloor of the Cocos plate, offshore Costa Rica. Extensive surveys of this region documented a Editor: M. Bickle 2 ∼14,500 km area of the seafloor with heat flux values that are 10–35% of those predicted from Keywords: conductive cooling models, and identified basement outcrops that serve as pathways for hydrothermal hydrothermal circulation circulation via recharge of bottom water and discharge of cool hydrothermal fluid. -
Causes of Sea Level Rise
FACT SHEET Causes of Sea OUR COASTAL COMMUNITIES AT RISK Level Rise What the Science Tells Us HIGHLIGHTS From the rocky shoreline of Maine to the busy trading port of New Orleans, from Roughly a third of the nation’s population historic Golden Gate Park in San Francisco to the golden sands of Miami Beach, lives in coastal counties. Several million our coasts are an integral part of American life. Where the sea meets land sit some of our most densely populated cities, most popular tourist destinations, bountiful of those live at elevations that could be fisheries, unique natural landscapes, strategic military bases, financial centers, and flooded by rising seas this century, scientific beaches and boardwalks where memories are created. Yet many of these iconic projections show. These cities and towns— places face a growing risk from sea level rise. home to tourist destinations, fisheries, Global sea level is rising—and at an accelerating rate—largely in response to natural landscapes, military bases, financial global warming. The global average rise has been about eight inches since the centers, and beaches and boardwalks— Industrial Revolution. However, many U.S. cities have seen much higher increases in sea level (NOAA 2012a; NOAA 2012b). Portions of the East and Gulf coasts face a growing risk from sea level rise. have faced some of the world’s fastest rates of sea level rise (NOAA 2012b). These trends have contributed to loss of life, billions of dollars in damage to coastal The choices we make today are critical property and infrastructure, massive taxpayer funding for recovery and rebuild- to protecting coastal communities. -
Microbiology of Seamounts Is Still in Its Infancy
or collective redistirbution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of The approval portionthe ofwith any articlepermitted only photocopy by is of machine, reposting, this means or collective or other redistirbution This article has This been published in MOUNTAINS IN THE SEA Oceanography MICROBIOLOGY journal of The 23, Number 1, a quarterly , Volume OF SEAMOUNTS Common Patterns Observed in Community Structure O ceanography ceanography S BY DAVID EmERSON AND CRAIG L. MOYER ociety. © 2010 by The 2010 by O ceanography ceanography O ceanography ceanography ABSTRACT. Much interest has been generated by the discoveries of biodiversity InTRODUCTION S ociety. ociety. associated with seamounts. The volcanically active portion of these undersea Microbial life is remarkable for its resil- A mountains hosts a remarkably diverse range of unusual microbial habitats, from ience to extremes of temperature, pH, article for use and research. this copy in teaching to granted ll rights reserved. is Permission S ociety. ociety. black smokers rich in sulfur to cooler, diffuse, iron-rich hydrothermal vents. As and pressure, as well its ability to persist S such, seamounts potentially represent hotspots of microbial diversity, yet our and thrive using an amazing number or Th e [email protected] to: correspondence all end understanding of the microbiology of seamounts is still in its infancy. Here, we of organic or inorganic food sources. discuss recent work on the detection of seamount microbial communities and the Nowhere are these traits more evident observation that specific community groups may be indicative of specific geochemical than in the deep ocean. -
A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods
water Review A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods Elahe Akbari 1,2, Seyed Kazem Alavipanah 1,*, Mehrdad Jeihouni 1, Mohammad Hajeb 1,3, Dagmar Haase 4,5 and Sadroddin Alavipanah 4 1 Department of Remote Sensing and GIS, Faculty of Geography, University of Tehran, Tehran 1417853933, Iran; [email protected] (E.A.); [email protected] (M.J.); [email protected] (M.H.) 2 Department of Climatology and Geomorphology, Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar 9617976487, Iran 3 Department of Remote Sensing and GIS, Shahid Beheshti University, Tehran 1983963113, Iran 4 Department of Geography, Humboldt University of Berlin, Unter den Linden 6, 10099 Berlin, Germany; [email protected] (D.H.); [email protected] (S.A.) 5 Department of Computational Landscape Ecology, Helmholtz Centre for Environmental Research UFZ, 04318 Leipzig, Germany * Correspondence: [email protected]; Tel.: +98-21-6111-3536 Received: 3 October 2017; Accepted: 16 November 2017; Published: 14 December 2017 Abstract: Oceans/Seas are important components of Earth that are affected by global warming and climate change. Recent studies have indicated that the deeper oceans are responsible for climate variability by changing the Earth’s ecosystem; therefore, assessing them has become more important. Remote sensing can provide sea surface data at high spatial/temporal resolution and with large spatial coverage, which allows for remarkable discoveries in the ocean sciences. The deep layers of the ocean/sea, however, cannot be directly detected by satellite remote sensors. -
Nutrient Dynamics with Groundwater–Seawater Interactions in a Beach Slope of a Steep Island, Western Japan
150 A New Focus on Groundwater–Seawater Interactions (Proceedings of Symposium HS1001 at IUGG2007, Perugia, July 2007). IAHS Publ. 312, 2007. Nutrient dynamics with groundwater–seawater interactions in a beach slope of a steep island, western Japan SHIN-ICHI ONODERA1, MITSUYO SAITO2, MASAKI HAYASHI2 & MISA SAWANO1 1 Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 7398521, Japan [email protected] 2 Graduate School of Biosphere Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 7398521, Japan Abstract To confirm the semi-diurnal and seasonal variation in nutrient flux with the dynamics in groundwater–seawater interaction, we conducted intensive observations at 25 piezometers in a tidal flat over a distance of 100 m across a steep-sloped island. Based on the chloride balance, groundwater was very - well-mixed with seawater under the tidal flat. Nitrate-nitrogen (NO3 -N) concentrations declined from >20 to near 0 mg L-1 along the groundwater flowpath from the hillslope to the tidal flat. In addition, nitrate concentrations in pore water of the tidal flat were lower (at 0.1 mg L-1) than in seawater. - These results suggest that the reduction process of NO3 -N occurred in both contaminated groundwater and seawater. Discharge of inorganic nitrogen by groundwater was confirmed offshore. The suspected source was nitrogen mineralization of organic compounds and seawater recirculation. Phosphorus was produced offshore and transported from the land area. Seasonal variations in nutrient dynamics at the tidal flat were also confirmed. Key words nutrient dynamics; groundwater; recirculated seawater; nitrate contamination INTRODUCTION Eutrophication and associated red tides in estuaries and inland seas are one of the critical environmental issues of this century. -
Recent Developments of Exploration and Detection of Shallow-Water Hydrothermal Systems
sustainability Article Recent Developments of Exploration and Detection of Shallow-Water Hydrothermal Systems Zhujun Zhang 1, Wei Fan 1, Weicheng Bao 1, Chen-Tung A Chen 2, Shuo Liu 1,3 and Yong Cai 3,* 1 Ocean College, Zhejiang University, Zhoushan 316000, China; [email protected] (Z.Z.); [email protected] (W.F.); [email protected] (W.B.); [email protected] (S.L.) 2 Institute of Marine Geology and Chemistry, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; [email protected] 3 Ocean Research Center of Zhoushan, Zhejiang University, Zhoushan 316000, China * Correspondence: [email protected] Received: 21 August 2020; Accepted: 29 October 2020; Published: 2 November 2020 Abstract: A hydrothermal vent system is one of the most unique marine environments on Earth. The cycling hydrothermal fluid hosts favorable conditions for unique life forms and novel mineralization mechanisms, which have attracted the interests of researchers in fields of biological, chemical and geological studies. Shallow-water hydrothermal vents located in coastal areas are suitable for hydrothermal studies due to their close relationship with human activities. This paper presents a summary of the developments in exploration and detection methods for shallow-water hydrothermal systems. Mapping and measuring approaches of vents, together with newly developed equipment, including sensors, measuring systems and water samplers, are included. These techniques provide scientists with improved accuracy, efficiency or even extended data types while studying shallow-water hydrothermal systems. Further development of these techniques may provide new potential for hydrothermal studies and relevant studies in fields of geology, origins of life and astrobiology. -
Lecture 4: OCEANS (Outline)
LectureLecture 44 :: OCEANSOCEANS (Outline)(Outline) Basic Structures and Dynamics Ekman transport Geostrophic currents Surface Ocean Circulation Subtropicl gyre Boundary current Deep Ocean Circulation Thermohaline conveyor belt ESS200A Prof. Jin -Yi Yu BasicBasic OceanOcean StructuresStructures Warm up by sunlight! Upper Ocean (~100 m) Shallow, warm upper layer where light is abundant and where most marine life can be found. Deep Ocean Cold, dark, deep ocean where plenty supplies of nutrients and carbon exist. ESS200A No sunlight! Prof. Jin -Yi Yu BasicBasic OceanOcean CurrentCurrent SystemsSystems Upper Ocean surface circulation Deep Ocean deep ocean circulation ESS200A (from “Is The Temperature Rising?”) Prof. Jin -Yi Yu TheThe StateState ofof OceansOceans Temperature warm on the upper ocean, cold in the deeper ocean. Salinity variations determined by evaporation, precipitation, sea-ice formation and melt, and river runoff. Density small in the upper ocean, large in the deeper ocean. ESS200A Prof. Jin -Yi Yu PotentialPotential TemperatureTemperature Potential temperature is very close to temperature in the ocean. The average temperature of the world ocean is about 3.6°C. ESS200A (from Global Physical Climatology ) Prof. Jin -Yi Yu SalinitySalinity E < P Sea-ice formation and melting E > P Salinity is the mass of dissolved salts in a kilogram of seawater. Unit: ‰ (part per thousand; per mil). The average salinity of the world ocean is 34.7‰. Four major factors that affect salinity: evaporation, precipitation, inflow of river water, and sea-ice formation and melting. (from Global Physical Climatology ) ESS200A Prof. Jin -Yi Yu Low density due to absorption of solar energy near the surface. DensityDensity Seawater is almost incompressible, so the density of seawater is always very close to 1000 kg/m 3. -
27. Chinook Trough Rifting and Hydrothermal Deposition at Sites 885 and 8861
Rea, D.K., Basov, I.A., Scholl, D.W., and Allan, J.F. (Eds.), 1995 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 145 27. CHINOOK TROUGH RIFTING AND HYDROTHERMAL DEPOSITION AT SITES 885 AND 8861 Gerald R. Dickens2 and Robert M. Owen2 ABSTRACT The Chinook Trough is a pronounced deep located in the central North Pacific Ocean that spans approximately 1500 km in a northeast-southwest direction. Geophysical and geomorphological considerations suggest that this feature is the southern litho- spheric scar marking initiation of Late Cretaceous north-south rifting within the ancient Farallon Plate. If this hypothesis is correct, then, by analogy to other active and passive mid-ocean rift zones, Late Cretaceous sediment deposited immediately south of the Chinook Trough should contain significant amounts of hydrothermal material deposited in association with the intraplate rifting event. Because the proposed tectonic origin for the Chinook Trough places seafloor south of the eastern end of the trough beneath the Cretaceous calcite compensation depth (CCD), expected hydrothermal components deposited during the Late Cretaceous at these locations also should lack carbonate dilution. Ocean Drilling Program Sites 885 and 886 were drilled approximately 60 km south of the northeast section of the Chinook Trough. High-resolution chemical and mineralogical analyses demonstrate that sediment deposited after 75-81 Ma at these sites contains an extensive record of hydrothermal deposition without associated carbonate. Various proxy indicators -
A Database for Ocean Acidification Assessment in the Iberian Upwelling
Earth Syst. Sci. Data, 12, 2647–2663, 2020 https://doi.org/10.5194/essd-12-2647-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. ARIOS: a database for ocean acidification assessment in the Iberian upwelling system (1976–2018) Xosé Antonio Padin, Antón Velo, and Fiz F. Pérez Instituto de Investigaciones Marinas, IIM-CSIC, 36208 Vigo, Spain Correspondence: Xosé Antonio Padin ([email protected]) Received: 13 March 2020 – Discussion started: 24 April 2020 Revised: 21 August 2020 – Accepted: 30 August 2020 – Published: 4 November 2020 Abstract. A data product of 17 653 discrete samples from 3343 oceanographic stations combining measure- ments of pH, alkalinity and other biogeochemical parameters off the northwestern Iberian Peninsula from June 1976 to September 2018 is presented in this study. The oceanography cruises funded by 24 projects were primarily carried out in the Ría de Vigo coastal inlet but also in an area ranging from the Bay of Biscay to the Por- tuguese coast. The robust seasonal cycles and long-term trends were only calculated along a longitudinal section, gathering data from the coastal and oceanic zone of the Iberian upwelling system. The pH in the surface waters of these separated regions, which were highly variable due to intense photosynthesis and the remineralization of organic matter, showed an interannual acidification ranging from −0:0012 to −0:0039 yr−1 that grew towards the coastline. This result is obtained despite the buffering capacity increasing in the coastal waters further inland as shown by the increase in alkalinity by 1:1±0:7 and 2:6±1:0 µmol kg−1 yr−1 in the inner and outer Ría de Vigo respectively, driven by interannual changes in the surface salinity of 0:0193±0:0056 and 0:0426±0:016 psu yr−1 respectively.