Dispersion in the ocean by physical, geochemical and biological processes

1986 ◽  
Vol 319 (1545) ◽  
pp. 177-187 ◽  
Keyword(s):  
Marine Environment ◽  
Food Chain ◽  
Deep Sea ◽  
Half Life ◽  
Radionuclide Transport ◽  
Biological Processes ◽  
Geochemical Processes ◽  
Biological Aspects ◽  
Transfer Mechanisms

The physical, geochemical and biological processes that lead to the dispersion of radionuclides throughout the marine environment and to interactions with man and his food chain are outlined. Although much remains to be understood about the details of these processes, certain limits may be put on radionuclide transport rates. Some of these limits are applicable to many situations, others are strongly dependent on the half-life, reactivity, etc., of the radionuclide or on the details of its source. Although physical and geochemical processes tend to dominate transfer mechanisms, the biological aspects of radionuclide transport attract much attention. It is shown that, even though our knowledge of deep-sea biology is far from perfect, certain quantifiable limits can also be put on these transport rates. An attempt is made to put these and other oceanic aspects of the deep-sea disposal of radionuclides into perspective.

scholarly journals MicroRNAs: Biological Regulators in Pathogen–Host Interactions

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 113 ◽  
Author(s):  
Stephanie Maia Acuña ◽  
Lucile Maria Floeter-Winter ◽  
Sandra Marcia Muxel
Keyword(s):  
Immune Response ◽  
Infectious Diseases ◽  
Small Rnas ◽  
Immune Cell ◽  
Fine Tuning ◽  
Biological Processes ◽  
Host Interactions ◽  
The Past ◽  
Biological Aspects

An inflammatory response is essential for combating invading pathogens. Several effector components, as well as immune cell populations, are involved in mounting an immune response, thereby destroying pathogenic organisms such as bacteria, fungi, viruses, and parasites. In the past decade, microRNAs (miRNAs), a group of noncoding small RNAs, have emerged as functionally significant regulatory molecules with the significant capability of fine-tuning biological processes. The important role of miRNAs in inflammation and immune responses is highlighted by studies in which the regulation of miRNAs in the host was shown to be related to infectious diseases and associated with the eradication or susceptibility of the infection. Here, we review the biological aspects of microRNAs, focusing on their roles as regulators of gene expression during pathogen–host interactions and their implications in the immune response against Leishmania, Trypanosoma, Toxoplasma, and Plasmodium infectious diseases.

scholarly journals Electron Transfer Initiated Reactions Photoinduced by Pterins

Pteridines ◽  
2011 ◽  
Vol 22 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Carolina Lorente ◽  
Gabriela Petroselli ◽  
M. Laura Dántola ◽  
Esther Oliveros ◽  
Andrés H. Thomas
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Redox Reactions ◽  
Type I ◽  
Biological Processes ◽  
Type Ii ◽  
Triplet Excited State ◽  
Oxygen Production ◽  
Production Type ◽  
Transfer Mechanisms

Abstract Interest in the photochemistry and photophysics of pterins has increased since the participation of this family of compounds in different photobiological processes has been suggested or demonstrated in recent decades. Pterins participate in relevant biological processes, such as metabolic redox reactions, and can photoinduce the oxidation of biomolecules through both electron transfer mechanisms (Type I) and singlet oxygen production (Type II). This article describes recent findings on electron transfer-initiated reactions photoinduced by the triplet excited state of pterins and connects them in the context of photosensitized processes of biological relevance.

Time and taphonomy: Actualistic evidence for time-averaging of benthic foraminiferal assemblages

1993 ◽  
Vol 6 ◽  
pp. 34-56 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
High Resolution ◽  
Ecosystem Management ◽  
Deep Sea ◽  
Time Averaging ◽  
Biological Processes ◽  
Exploration And Exploitation ◽  
Short Term ◽  
Resource Exploration ◽  
To Come ◽  
Paleoclimate Modelling

For more than half a century, microfossils–especially foraminifera–have been widely used as stratigraphic markers and paleoenvironmental indicators. Although increasing emphasis has been placed on their use in high-resolution paleoclimate studies, the time-scales involved in most microfossil-based stratigraphic investigations have remained relatively coarse (hundreds-of-thousands to millions of years). My intent herein is to try to come to grips with the interplay between time-averaging of benthic foraminiferal assemblages and stratigraphic resolution, and the implications for recognition of short-term physical and biological processes. These sorts of considerations deserve much closer scrutiny as the applied Earth sciences continue to move from a base of resource exploration and exploitation to one of paleoclimate modelling and ecosystem management (Martin, 1991; Corliss, 1993). The potential stratigraphic and paleoenvironmental resolution of foraminiferal assemblages is assessed using concepts derived from the age analysis of deep-sea assemblages.

The transfer of65Zn and 59Fe along a Fucus serratus (L.)→ Littorina obtusata (L.) food chain

1975 ◽  
Vol 55 (3) ◽  
pp. 583-610 ◽  
Author(s):  
M. L. Young
Keyword(s):  
Trace Metals ◽  
Radiation Exposure ◽  
Marine Environment ◽  
Food Chain ◽  
Sea Water ◽  
Food Chains ◽  
Fresh Weight ◽  
Littorina Obtusata ◽  
Fucus Serratus ◽  
Marine Food

In marine organisms the fresh-weight concentrations of the trace metals zinc and iron are 102–105 times the concentrations in sea water. Study of the transfer of these metals along marine food chains is of interest because of the possibility of their being pollutants of the marine environment. Also65Zn and 65Fe are released to the marine environment and have been found, in many instances, to be the predominant radionuclides in food chains leading to man (Lowman, Palumbo & South, 1957; Lowman, 1960; Osterberg, Pearcy & Curl, 1964; Preston, 1967). The transfer of these metals along marine food chains is thus of interest also in the context of human radiation exposure.

scholarly journals John Marmion Edmond. 27 April 1943 — 10 April 2001

2008 ◽  
Vol 54 ◽  
pp. 137-159
Author(s):  
Henry Elderfield ◽  
Edward A. Boyle
Keyword(s):  
Deep Sea ◽  
Rift Valley ◽  
Hot Springs ◽  
Chemical Elements ◽  
Geochemical Processes ◽  
Rare Metals ◽  
Sea Floor ◽  
Quantitative Understanding ◽  
Rift Valley Lakes ◽  
Isotope Systematics

John Edmond was a geochemist the unifying theme of whose research was a quantitative understanding of the processes involved in the transfer of the chemical elements into and out of the oceans; in short, what controls ocean chemistry. He achieved this through oceanographic explorations sampling ocean waters for rare metals and explorations of hot springs on the deep sea floor, rivers from the Amazon to Siberia, and the rift valley lakes of Africa. This accompanied a strong background in chemistry and an almost reverent recognition of the value of data. John challenged established paradigms and pioneered developments in element and isotope systematics as applied to geochemical processes. He will alsobe remembered for his enthusiasm, his insight, his honesty, and his defence of anyone or any group he felt was badly treated.

Ninety Years' High-pressure Research

1972 ◽  
Vol 73 ◽  
pp. 279-285
Author(s):  
H. Flügel
Keyword(s):  
Nineteenth Century ◽  
High Pressure ◽  
Marine Environment ◽  
Deep Sea ◽  
Extreme Pressure ◽  
Animal Life ◽  
General Belief ◽  
Overwhelming Evidence ◽  
Antarctic Expedition ◽  
Abyssal Fauna

The question as to the existence of life at great depths was still a matter of controversy in the last century. In spite of the fact that the remains of living animals were recovered from several hundreds of metres, many marine biologists hesitated to believe that animal life could exist in deep-sea conditions. In 1841, Sir James Clark Ross, the leader of the British Antarctic Expedition, claimed:‘… and although contrary to the general belief of naturalists, I have no doubt that from however great a depth we may be able to bring the mud and stones of the bed of the ocean, we shall find them teeming with animal life; the extreme pressure at the greatest depth does not appear to affect these creatures; hitherto we have not been able to determine this point beyond a thousand fathoms, but from that depth several shellfish have been brought up with the mud’ (Murray 1895, p. 79). Edward Forbes, naturalist on H.M.S.S. Beacon, for instance, referred to the marine environment in excess of 550 m as the ‘azoic zone’. But the classical deep-sea expeditions in the second half of the nineteenth century, among others the famous voyage of the Challenger, produced overwhelming evidence for a more or less abundant abyssal fauna.

Sea Fishing at Salango (Manabí Province, Ecuador) During the Middle Formative Machalilla Phase

2012 ◽  
Vol 23 (2) ◽  
pp. 195-214 ◽  
Author(s):  
Philippe Béarez ◽  
Patrick Gay ◽  
Richard Lunniss
Keyword(s):  
Marine Environment ◽  
Fish Species ◽  
Deep Sea ◽  
Yellowfin Tuna ◽  
Tuna Fishing ◽  
Late Formative ◽  
Fish Remains ◽  
Middle Formative

AbstractFormative Ecuadorian coastal societies possessed the technologies and skills necessary not only for fishing, but also for deep-sea navigation. Although marine shellfish are acknowledged as significant both for dietary and religious purposes, the importance of sea-fishing is rarely highlighted or explored. In order to help evaluate more fully the significance of the sea in the Ecuadorian Formative, this paper presents recently studied evidence, excavated at the Salango site, in the Province of Manabí, for local off-shore tuna fishing during the Middle Formative Machalilla phase (ca. 1500–900 B.C.), where Scombrids constituted 80 percent of recovered fish remains. The results are then compared with those obtained from other Machalilla sites. Finally, data from the subsequent Late Formative Engoroy phase (ca. 900–100 B.C.) indicate that while Scombrid fishing continued to predominate at Salango, species capture changed through time, with a shift from yellowfin tuna in the Machalilla phase to black skipjacks in Engoroy times. It is suggested that the decline in tuna capture reflects not so much change in fishing strategy as change in the populations of fish species reaching the local marine environment.

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