Cyanobacteria: The Great Liberators

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Primary Production ◽  
Source Water ◽  
Biological Production ◽  
Planet Surface ◽  
Photosynthetic Organisms ◽  
Almost Everywhere ◽  
Life On Earth ◽  
Trace Constituents ◽  
First Time ◽  
Evolution Of Oxygen

This chapter discusses the importance of cyanobacteria. The evolution of cyanobacteria brought the biological production of oxygen to Earth for the first time. This led, in turn, to the eventual accumulation of oxygen in the atmosphere and to the widespread evolution of oxygen-utilizing organisms. However, the importance of cyanobacteria goes beyond this. Cyanobacteria were the first photosynthetic organisms on Earth to use water as a source of electrons. Unlike the sulfide, Fe2+, and H2 used by anoxygenic phototrophic organisms, water is almost everywhere on the planet surface. This means that biological production on Earth was no longer limited by the electron source (water in this case), but rather by nutrients and other trace constituents making up the cells. In the end, the use of water in photosynthesis resulted in an increase in rates of primary production on Earth by probably somewhere between a factor of ten to a thousand. For the first time, life on Earth became truly plentiful. With the evolution of cyanobacteria, Earth was on its way to becoming a green planet.

scholarly journals Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and contribution to primary production

2006 ◽  
Vol 3 (4) ◽  
pp. 895-959 ◽  
Author(s):  
J.-P. Gattuso ◽  
B. Gentili ◽  
C. M. Duarte ◽  
J. A. Kleypas ◽  
J. J. Middelburg ◽  
...  
Keyword(s):  
Primary Production ◽  
Surface Area ◽  
Coastal Zone ◽  
Benthic Communities ◽  
Light Availability ◽  
Coastal Ocean ◽  
Shelf Area ◽  
Primary Producers ◽  
Benthic Primary Production ◽  
Photosynthetic Organisms

Abstract. One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS) data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface of the coastal zone receiving an irradiance greater than Ez: PaNon-polar=28.80−16.69 log10(Ez)+0.84 log102(Ez)+0.83 log103(Ez) PaArctic=16.01−15.67 log10(Ez)+2.03 log102(Ez)+1.00 log103(Ez) Data on the constraint of light availability on the major benthic primary producers and net primary production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m). The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1) light does not limit the distribution of primary producers and (2) net community production (NCP, the balance between gross primary production and respiration) is positive. Positive benthic NCP can occur over 37% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, and the relatively limited biological information available, are discussed.

The Two Manias: A Study of the Evolution of the Modern Concept of Mania

1981 ◽  
Vol 138 (2) ◽  
pp. 89-99 ◽  
Author(s):  
Edward Hare
Keyword(s):  
Nineteenth Century ◽  
Modern Concept ◽  
Dementia Praecox ◽  
Sixth Edition ◽  
Present Essay ◽  
Manic Depressive ◽  
Almost Everywhere ◽  
The World ◽  
Functional Psychoses ◽  
First Time

In the year 1899 there occurred an event which has had great consequence for psychiatry. This was the publication of the sixth edition of Emil Kraepelin's textbook, where he introduced for the first time his distinction between manic-depressive insanity and dementia praecox. It was a distinction which rapidly became accepted almost everywhere in the world, and it still forms the basis of our thinking about the nature of the functional psychoses. Kraepelin's concept of mania was quite different from the concept of mania held during most of the nineteenth century; and so, historically speaking, there are two manias, more or less sharply separated by the Kraepelinian revolution. The purpose of the present essay is to give some account of the term mania in its pre-Kraepelinian sense and of the events which led Kraepelin to his new concept; and also (in Part II) to put forward a new idea of why this revolution came about.

scholarly journals Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and their contribution to primary production

2006 ◽  
Vol 3 (4) ◽  
pp. 489-513 ◽  
Author(s):  
J.-P. Gattuso ◽  
B. Gentili ◽  
C. M. Duarte ◽  
J. A. Kleypas ◽  
J. J. Middelburg ◽  
...  
Keyword(s):  
Primary Production ◽  
Surface Area ◽  
Coastal Zone ◽  
Benthic Communities ◽  
Light Availability ◽  
Coastal Ocean ◽  
Net Community Production ◽  
Benthic Primary Production ◽  
Photosynthetic Organisms ◽  
Community Production

Abstract. One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS) data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface (S) of the coastal zone receiving an irradiance greater than Ez (in mol photons m−2 d−1): SNon-polar = 29.61 − 17.92 log10(Ez) + 0.72 log102(Ez) + 0.90 log103(Ez) SArctic = 15.99 − 13.56 log10(Ez) + 1.49 log102(Ez) + 0.70 log103(Ez) Data on the constraint of light availability on the major benthic primary producers and net community production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m). The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1) light does not limit the distribution of primary producers and (2) net community production (NCP, the balance between gross primary production and community respiration) is positive. Positive benthic NCP can occur over 33% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, the lack of global information on the benthic nepheloid layer, and the relatively limited biological information available, are discussed.

Seasonal variations in the Indian Ocean along 110°E. IV. Primary production

1969 ◽  
Vol 20 (1) ◽  
pp. 65 ◽  
Author(s):  
HR Jitts
Keyword(s):  
Indian Ocean ◽  
Primary Production ◽  
Seasonal Variations ◽  
High Productivity ◽  
Photosynthetic Organisms ◽  
South Indian ◽  
Daily Rate ◽  
Deep Layers ◽  
Equatorial Upwelling ◽  
The Indian Ocean

Mean productivity (light saturated photosynthesis), Ps, for the meridian rose from 50 mg C/(hr m²) in August 1962 to a maximum of 62 in October, then fell to a minimum of 4 in January, whereafter it rose slowly to 25 in April-May, then sharply to 45 in late May, and remained at that level till August 1963. Mean Ps for the year was 37 mg C/(hr m²). The depth of the layer of photosynthetic organisms varied between 130 m in October and 60 m in January, with a mean of 85 m. Maximum Ps occurred at 25 m in 36% of the stations, at 0 m in 29 %, and at 50 m in 24%. In January-February the whole meridian was occupied by waters of low productivity, approximately 4 mg C/(hr m²) from the centre of the south Indian Ocean. In April-May the Ps remained uniform along the meridian but rose to 24. At other times four latitudinal intervals along the meridian, with distinctive seasonal variations of productivity characteristics, were found. From 9 to 15°S., waters with high Ps (69 mg C/(hr m²)), and sharp stratification at 50 m, caused by equatorial upwelling, occurred from May to October. From 15 to 24 and 24 to 30°S., waters with high Ps (60 mg Cl(hr m²) and (100 m) deep layers of photosynthetic organisms were found during October-November and May-July respectively. From 30 to 32�S., waters of high productivity (70 mg C/(hr m²)) and a deep layer (100 m) were found in the period July-August. The daily rate of primary production, Pa, of the whole meridian varied from 0.13 g C/(day m²) in August to 0.08 from October to early May, rising sharply in late May to 0.18 and again in early August to 0.27. The depth of the euphotic layer varied between 76 m in October and 63 m in July-August, with a mean of 68 m.

Vikings on the Plains of Chryse and Utopia

2020 ◽  
pp. 147-160
Author(s):  
David A. Weintraub
Keyword(s):  
Carbon Dioxide ◽  
Martian Atmosphere ◽  
Life On Earth ◽  
First Time

This chapter refers to Viking 1, which landed on the Plains of Gold, Chryse Planitia, on Mars on July 20, 1976, followed by Viking 2, which touched down on Utopia Planitia, six weeks later. It details the landing of the two Vikings in two different locations, which allowed human-directed science experiments to take place for the first time on the surface of Mars. It also mentions the planetary scientists who discovered that the Martian atmosphere was thin and mostly made of carbon dioxide. The chapter describes the Mariner-imaging surveys of the surface of Mars, which shows the planet covered with cratered plains, a small number of enormous volcanoes, and a significant number of narrow features that looked like ancient, dried-out riverbeds and lengthy outwash channels. It confirms whether the atmosphere of Mars contains any nitrogen, as the gas is critical to life on Earth.

Evidence of seasonal reproduction in the Atlantic vent mussel Bathymodiolus azoricus, and an apparent link with the timing of photosynthetic primary production

2006 ◽  
Vol 86 (6) ◽  
pp. 1363-1371 ◽  
Author(s):  
D.R. Dixon ◽  
D.M. Lowe ◽  
P.I. Miller ◽  
G.R. Villemin ◽  
A. Colaço ◽  
...  
Keyword(s):  
Primary Production ◽  
Deep Sea ◽  
Euphotic Zone ◽  
Seasonal Reproduction ◽  
Mid Atlantic Ridge ◽  
Time Series Studies ◽  
Dominant Member ◽  
Menez Gwen ◽  
First Time ◽  
The Relationship

Here we present evidence of seasonal reproduction in the deep-sea vent mussel Bathymodiolus azoricus, a dominant member of the Mid-Atlantic Ridge (MAR) hydrothermal fauna in the Azores region. This is the first time that seasonal reproduction has been suggested for any deep-sea vent organism. This discovery was made possible by the use of novel, acoustically-retrievable cages, which allowed us to extend the frequency and temporal range of sampling that was previously limited to the summer months. The main spawning peak, at the Menez Gwen vent field (840 m) occurs in late December–January and shows a correlation with a winter–spring bloom in primary production in the euphotic zone. Our results suggest that this surface-derived material may act as both a food source for the dispersing mussel larvae and as a reproductive cue/supplementary nutritional source for the adult mussels. Further evidence of a dependence on photosynthetic inputs comes from the relationship between particulate feeding levels, which themselves correlate with the phytoplankton peak, and the amounts of storage tissue in the mantle, which ultimately gets converted into gonad. Thus, the pattern and energetics of reproduction in the Atlantic vent mussel B. azoricus closely resembles that found in the coastal mussel Mytilus edulis, which has been described as an adaptation for optimizing the timing of reproduction against a background of seasonally-varying food availability. This discovery emphasizes the complexity of the nutritional pathways found in some deep-sea chemosynthetic environments and highlights the need for more time-series studies.

scholarly journals Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

2016 ◽  
Vol 13 (1) ◽  
pp. 323-340 ◽  
Author(s):  
S. Walter ◽  
A. Kock ◽  
T. Steinhoff ◽  
B. Fiedler ◽  
P. Fietzek ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Molecular Hydrogen ◽  
Transport Model ◽  
Isotopic Signature ◽  
Water Masses ◽  
Atmospheric Measurements ◽  
Biological Production ◽  
Northern Atlantic ◽  
Main Components ◽  
First Time

Abstract. Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during 5 cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauritania.The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (−629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (−249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with the biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production, a significant different source should be considered.The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.

Effects of a fluctuation in Fraser River discharge of primary production in the central Strait of Georgia, British Columbia, Canada

1997 ◽  
Vol 54 (5) ◽  
pp. 1015-1024 ◽  
Author(s):  
K Yin ◽  
P J Harrison ◽  
R J Beamish
Keyword(s):  
British Columbia ◽  
Primary Production ◽  
River Discharge ◽  
Euphotic Zone ◽  
Early Summer ◽  
Phytoplankton Production ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Chl A ◽  
First Time

High-resolution vertical profiles of salinity, temperature, fluorescence, and nutrients (NO3 and SiO4) were taken along a transect in the central Strait of Georgia, British Columbia. The Fraser River discharge increased rapidly over 4 days and then decreased over the following 3 days (June 16-19, 1991). The thickness and extent of the estuarine plume increased as a response to the increased river discharge. As the estuarine plume flowed seaward, the nutricline (NO3) became shallower and broader, resulting in an increase in NO3 in the euphotic zone. Entrainment of NO3 may explain the increase in NO3 in the surface layer, and the amount of NO3 entrained was estimated to be 5-10 times higher than river-borne NO3. The utilization of entrained nutrients increased Chl a concentrations and primary production to levels comparable with spring bloom values. Our results clearly demonstrated for the first time that entrainment of nutrients and phytoplankton production in the central Strait of Georgia are closely coupled to fluctuations in the Fraser River discharge as the estuarine plume moves seaward. The timing and magnitude of the May-June freshet could control the entrainment of nutrients and thus maintain high primary productivity in late spring - early summer.

scholarly journals Photosynthesis: Light and Life

2013 ◽  
Vol 35 (5) ◽  
pp. 4-7
Author(s):  
James W. Murray
Keyword(s):  
Electron Acceptor ◽  
Energy Input ◽  
Oxygen Molecule ◽  
Crucial Importance ◽  
Terminal Electron Acceptor ◽  
Photosynthetic Organisms ◽  
Energy Technologies ◽  
The Earth ◽  
Life On Earth ◽  
Single Oxygen

Complex life on Earth requires oxygen as the terminal electron acceptor in the respiratory chain. However, the lifetime of a single oxygen molecule in the atmosphere is only 4500 years. Oxygen is continually being replenished by the action of photosynthetic organisms, using the only substantial energy input to the Earth, sunlight. How this light energy is harvested and used is of fundamental biological importance, and may be of crucial importance in developing sustainable energy technologies.

scholarly journals Marine natural products: the new generation of pharmacotherapeutics

2021 ◽  
Vol 10 (7) ◽  
pp. 876
Author(s):  
Rajeev Goel ◽  
Binny Mahendru ◽  
Tushar Saini
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Bacterial Infections ◽  
Sea Urchins ◽  
Sea Anemones ◽  
Planet Surface ◽  
Sea Bed ◽  
Life On Earth ◽  
Micro Organisms ◽  
New Generation

The biomedical potential of the sea has gone largely unexplored so far, despite the fact that it covers three quarters of the planet surface and the fact that life on Earth originated from the sea. However, with the arrival of the professional deep sea divers, the marine researchers have gained access to all sorts of marine creatures like sponges, corals, sea urchins, sea squirts, hydroids, sea anemones, fishes and mollusks as well as to varied types of sea plants including algae and the other micro-organisms embedded in the sea bed. The biomedical scientists are exploiting these all to extract marine natural products (MNPs) having pharmacological properties that may one day cure long list of illnesses varying from bacterial infections to cancer, Alzheimer's and AIDS and was the focus of this review article.

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