Trace-element budgets in the Ohio/Sunbury shales of Kentucky: Constraints on ocean circulation and primary productivity in the Devonian–Mississippian Appalachian Basin

2008 ◽  
Vol 265 (1-2) ◽  
pp. 14-29 ◽  
Author(s):  
R.B. Perkins ◽  
D.Z. Piper ◽  
C.E. Mason
Keyword(s):  
Trace Element ◽  
Ocean Circulation ◽  
Primary Productivity ◽  
Appalachian Basin ◽  
Element Budgets

scholarly journals Biogeochemistry of the North Atlantic during oceanic anoxic event 2: role of changes in ocean circulation and phosphorus input

2014 ◽  
Vol 11 (4) ◽  
pp. 977-993 ◽  
Author(s):  
I. Ruvalcaba Baroni ◽  
R. P. M. Topper ◽  
N. A. G. M. van Helmond ◽  
H. Brinkhuis ◽  
C. P. Slomp
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Primary Productivity ◽  
Low Oxygen ◽  
Deep Basin ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Atlantic

Abstract. The geological record provides evidence for the periodic occurrence of water column anoxia and formation of organic-rich deposits in the North Atlantic Ocean during the mid-Cretaceous (hereafter called the proto-North Atlantic). Both changes in primary productivity and oceanic circulation likely played a role in the development of the low-oxygen conditions. Several studies suggest that an increased input of phosphorus from land initiated oceanic anoxic events (OAEs). Other proposed mechanisms invoke a vigorous upwelling system and an ocean circulation pattern that acted as a trap for nutrients from the Pacific Ocean. Here, we use a detailed biogeochemical box model for the proto-North Atlantic to analyse under what conditions anoxia could have developed during OAE2 (94 Ma). The model explicitly describes the coupled water, carbon, oxygen and phosphorus cycles for the deep basin and continental shelves. In our simulations, we assume the vigorous water circulation from a recent regional ocean model study. Our model results for pre-OAE2 and OAE2 conditions are compared to sediment records of organic carbon and proxies for photic zone euxinia and bottom water redox conditions (e.g. isorenieratane, carbon/phosphorus ratios). Our results show that a strongly elevated input of phosphorus from rivers and the Pacific Ocean relative to pre-OAE2 conditions is a requirement for the widespread development of low oxygen in the proto-North Atlantic during OAE2. Moreover, anoxia in the proto-North Atlantic is shown to be greatly influenced by the oxygen concentration of Pacific bottom waters. In our model, primary productivity increased significantly upon the transition from pre-OAE2 to OAE2 conditions. Our model captures the regional trends in anoxia as deduced from observations, with euxinia spreading to the northern and eastern shelves but with the most intense euxinia occurring along the southern coast. However, anoxia in the central deep basin is difficult to achieve in the model. This suggests that the ocean circulation used in the model may be too vigorous and/or that anoxia in the proto-North Atlantic was less widespread than previously thought.

Trace element budgets of enmched and depleted mantle

1998 ◽  
Vol 43 (S1) ◽  
pp. 46-46
Author(s):  
S. L. Goldstein ◽  
A. W. Hofmann ◽  
D. M. Miller ◽  
C. H. Langmuir
Keyword(s):  
Trace Element ◽  
Depleted Mantle ◽  
Element Budgets

Major, minor and trace element budgets in the Plynlimon afforested catchments (Wales): general trends, and effects of felling and climate variations

1994 ◽  
Vol 157 (1-4) ◽  
pp. 139-156 ◽  
Author(s):  
Patrick Durand ◽  
Colin Neal ◽  
Hazel A. Jeffery ◽  
Geoffrey P. Ryland ◽  
Margaret Neal
Keyword(s):  
Trace Element ◽  
Climate Variations ◽  
Element Budgets

scholarly journals The global marine phosphorus cycle: sensitivity to oceanic circulation

2006 ◽  
Vol 3 (5) ◽  
pp. 1587-1629 ◽  
Author(s):  
C. P. Slomp ◽  
P. Van Cappellen
Keyword(s):  
Calcium Phosphate ◽  
Primary Production ◽  
Ocean Circulation ◽  
Primary Productivity ◽  
Deep Sea ◽  
Open Ocean ◽  
Depositional Environments ◽  
Global Ocean ◽  
Oceanic Circulation ◽  
Continental Shelves

Abstract. A new mass balance model for the coupled marine cycles of phosphorus (P) and carbon (C) is used to examine the relationships between oceanic circulation, primary productivity, and sedimentary burial of reactive P and particulate organic C (POC), on geological time scales. The model explicitly represents the exchanges of water and particulate matter between the continental shelves and the open ocean, and it accounts for the redox-dependent burial of POC and the various forms of reactive P (iron(III)-bound P, particulate organic P (POP), authigenic calcium phosphate, and fish debris). Steady state and transient simulations indicate that a slowing down of global ocean circulation decreases primary production in the open ocean, but increases that in the coastal ocean. The latter is due to increased transfer of soluble P from deep ocean water to the shelves, where it fuels primary production and causes increased reactive P burial. While authigenic calcium phosphate accounts for most reactive P burial ocean-wide, enhanced preservation of fish debris may become an important reactive P sink in deep-sea sediments during periods of ocean anoxia. Slower ocean circulation globally increases POC burial, because of enhanced POC preservation under anoxia in deep-sea depositional environments and higher primary productivity along the continental margins. In accordance with geological evidence, the model predicts increased accumulation of reactive P on the continental shelves during and following periods of ocean anoxia.

Use of Foraminifera in Climate Science

2019 ◽  
Author(s):  
Gerhard Schmiedl
Keyword(s):  
Stable Isotope ◽  
Trace Element ◽  
Ocean Circulation ◽  
Transfer Functions ◽  
Isotope Composition ◽  
Sediment Cores ◽  
Environmental Data ◽  
Geochemical Data ◽  
Climate History ◽  
Sediment Types

The understanding of past changes in climate and ocean circulation is to a large extent based on information from marine sediments. Marine deposits contain a variety of microfossils, which archive (paleo)-environmental information, both in their floral and faunal assemblages and in their stable isotope and trace element compositions. Sampling campaigns in the late 19th and early 20th centuries were dedicated to the inventory of sediment types and microfossil taxa. With the initiation of various national and international drilling programs in the second half of the 20th century, sediment cores were systematically recovered from all ocean basins and since then have shaped our knowledge of the oceans and climate history. The stable oxygen isotope composition of foraminiferal tests from the sediment cores delivered a continuous record of late Cretaceous–Cenozoic glaciation history. This record impressively proved the effects of periodic changes in the orbital configuration of the Earth on climate on timescales of tens to hundreds of thousands of years, described as Milankovitch cycles. Based on the origination and extinction patterns of marine microfossil groups, biostratigraphic schemes have been established, which are readily used for the dating of sediment successions. The species composition of assemblages of planktic microfossils, such as planktic foraminifera, radiolarians, dinoflagellates, coccolithophorids, and diatoms, is mainly related to sea-surface temperature and salinity but also to the distribution of nutrients and sea ice. Benthic microfossil groups, in particular benthic foraminifera but also ostracods, respond to changes in water depth, oxygen, and food availability at the sea floor, and provide information on sea-level changes and benthic-pelagic coupling in the ocean. The establishment and application of transfer functions delivers quantitative environmental data, which can be used in the validation of results from ocean and climate modeling experiments. Progress in analytical facilities and procedures allows for the development of new proxies based on the stable isotope and trace element composition of calcareous, siliceous, and organic microfossils. The combination of faunal and geochemical data delivers information on both environmental and biotic changes from the same sample set. Knowledge of the response of marine microorganisms to past climate changes at various amplitudes and pacing serves as a basis for the assessment of future resilience of marine ecosystems to the anticipated impacts of global warming.

Modulation of the Southern Ocean cadmium isotope signature by ocean circulation and primary productivity

2011 ◽  
Vol 305 (1-2) ◽  
pp. 83-91 ◽  
Author(s):  
W. Abouchami ◽  
S.J.G. Galer ◽  
H.J.W. de Baar ◽  
A.C. Alderkamp ◽  
R. Middag ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Primary Productivity ◽  
Isotope Signature

scholarly journals Trace Element Budgets in Lake Baikal Question the Dominant Effect of Salinity in Estuarine Removal Processes

2020 ◽  
Author(s):  
Tim Jesper Suhrhoff ◽  
Jörg Dominik Rickli ◽  
Elena G. Vologina ◽  
Viet Pham ◽  
Moustafa Belhadj ◽  
...  
Keyword(s):  
Trace Element ◽  
Lake Baikal ◽  
Dominant Effect ◽  
Element Budgets ◽  
Removal Processes

scholarly journals The global marine phosphorus cycle: sensitivity to oceanic circulation

2007 ◽  
Vol 4 (2) ◽  
pp. 155-171 ◽  
Author(s):  
C. P. Slomp ◽  
P. Van Cappellen
Keyword(s):  
Calcium Phosphate ◽  
Primary Production ◽  
Ocean Circulation ◽  
Primary Productivity ◽  
Deep Sea ◽  
Open Ocean ◽  
Depositional Environments ◽  
Global Ocean ◽  
Oceanic Circulation ◽  
Continental Shelves

Abstract. A new mass balance model for the coupled marine cycles of phosphorus (P) and carbon (C) is used to examine the relationships between oceanic circulation, primary productivity, and sedimentary burial of reactive P and particulate organic C (POC), on geological time scales. The model explicitly represents the exchanges of water and particulate matter between the continental shelves and the open ocean, and it accounts for the redox-dependent burial of POC and the various forms of reactive P (iron(III)-bound P, particulate organic P (POP), authigenic calcium phosphate, and fish debris). Steady state and transient simulations indicate that a slowing down of global ocean circulation decreases primary production in the open ocean, but increases that in the coastal ocean. The latter is due to increased transfer of soluble P from deep ocean water to the shelves, where it fuels primary production and causes increased reactive P burial. While authigenic calcium phosphate accounts for most reactive P burial ocean-wide, enhanced preservation of fish debris may become an important reactive P sink in deep-sea sediments during periods of ocean anoxia. Slower ocean circulation globally increases POC burial, because of enhanced POC preservation under anoxia in deep-sea depositional environments and higher primary productivity along the continental margins. In accordance with geological evidence, the model predicts increased accumulation of reactive P on the continental shelves during and following periods of ocean anoxia.

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