The Biological Productivity Of the Ocean

11 Key excerpts on "The Biological Productivity Of the Ocean"

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  Phytoplankton Productivity

  Carbon Assimilation in Marine and Freshwater Ecosystems

  • Peter J. le B. Williams, David N. Thomas, Colin S. Reynolds, Peter J. le B. Williams, David N. Thomas, Colin S. Reynolds(Authors)
  • 2008(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Technical limitations prevented accurate measurement of plankton productivity before World War II, although good qualitative descriptions of the dynamics of plankton productivity were achieved. After World War II a greatly expanded international cohort of biological oceanographers, newly armed with Steemann Nielsen's 14 C uptake method, enthusiastically set out to answer three key questions: How productive is the ocean? What is the regional pattern of productivity? And what is the seasonal pattern of productivity? As it turned out, answers did not come easily because temporal and spatial variability of the ocean was more important than had been suspected and also because the sensitive 14 C method revealed other problems that had to be addressed before the original questions could be answered satisfactorily. Never-theless, in the period of 1950 to 1970, biological oceanography marked a series of milestones as answers to the questions originally posed by Hensen, Gran and Steemann Nielsen became available. This history is, therefore, a success story ± a story in which Steemann Nielsen plays a pivotal role: he bridged the pre-war and 40 Phytoplankton Productivity post-war periods and armed the struggling discipline of biological oceanography with the technology needed to succeed in the new era. Acknowledgements We gratefully acknowledge Felicity Pors of the Niels Bohr Archive; David Talbert, Duke University Marine Laboratory librarian; Dr Annette Vogt, Scholar in Resi-dence at the Max Planck Institute for the History of Science; and Lady Lise Schou Wilkinson for their help. They provided essential information or directed us to appropriate sources. References Alverson, D.L., Longhurst, A.R. & Gulland, J.A. (1970) How much food from the sea? Science 168 , 503. Atkins, W.R.G. (1926) A quantitative consideration of some factors concerned in plant growth in water. Part II. Some chemical factors. Journal du Conseil International pour l'Exploration de la Mer 1 , 99±126.

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  Fundamentals of Limnology

  • Munshi, Jayshree Datta(Authors)
  • 2021(Publication Date)
  • Daya Publishing House

    (Publisher)

  Biological Productivity And Energetics The biological productivity of any system whether aquatic or terrestrial involves the trapping of solar energy by chlorophyll bearing plants and its transformation within the system by different organisms at different trophic levels. The energy that enters the earth’s surface as light is balanced by the energy that leaves the earth’s surface as invisible radiation. The rate at which energy is stored by green plants is called primary productivity and by the heterotrophs secondary productivity. The essence of life is the progression of such changes as growth, self-duplication and synthesis of complex relationships of matter which actually depends upon the biological productivity and energetics within the system. Concept of Productivity There are four successive steps in the process of biological productivity: Gross Primary Productivity It is the total rate of photosynthesis including the organic matter used up in respiration during the measurement period. This is also known as total photosynthesis or total assimilation. Net Primary Productivity It is the rate of storage of organic matter in plant tissues in excess of the respiratory use by the plants during the measurement period. This is also called apparent photosynthesis or net assimilation. This ebook is exclusively for this university only. Cannot be resold/distributed. Net Community Productivity It is the rate of storage of organic matter not used by heterotrophs during the growing season or a year. Actually this is the net primary production minus the heterotrophic consumption during the period of consideration. Secondary Productivity It is the rate of energy storage at consumer level. The consumers utilize food materials produced with the respiratory loss at authotrophic level and convert them to different tissues by the overall process of assimilation. The secondary productivity should not be divided into gross and net amounts.

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  Elements of Marine Ecology

  • Frances Dipper, R V TAIT (DECD), FRANCES DIPPER(Authors)
  • 1998(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  5 Organic production in the sea 5.1 Primary production The synthesis of organic compounds from the inorganic constituents of seawater by the activity of organisms is termed production . It is effected almost entirely by the photosynthetic activity of marine plants. The raw materials are water (H 2 O), carbon dioxide (CO 2 ) and various other substances known as nutrients. The latter are mainly inorganic ions, principally nitrate and phosphate. Chlorophyll-containing plants, by making use of light energy, are able to combine these simple substances to synthesize complex organic molecules. This is termed gross primary production . The chief products are the three major categories of food materials, namely carbohydrates, proteins and fats (Steeman Nielsen, 1975). Oxygen, derived from the water, is produced as a byproduct. The process involves a number of steps but can be summarized by the following very general equation: Photosynthesis → 6CO 2 6H 2 O J C 6 H 12 O 6 6O 2 Carbon dioxide Water Carbohydrate Respiration Oxygen Some of the organic material manufactured by plants is broken down again by an oxidative reaction, to an inorganic state by the plants themselves in the course of their respiration. Hence the equation is written as a reversible one. The remainder is referred to as net primary production and much of this becomes new plant tissue. This is of major importance as the source of food for herbivorous animals. The animal population of the sea therefore depends, directly or indirectly, upon the net primary production. By far the greater part of primary production in the sea is performed by the phytoplankton (Raymont, 1963, 1966). Under favourable conditions this is capable of remarkably rapid growth, sometimes producing its own weight of new organic material within 24 hours, a rate greater than that achievable by land plants.

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  Plankton & Productivity in the Oceans

  Volume 1: Phytoplankton

  • J. E. G. Raymont(Author)
  • 2014(Publication Date)
  • Pergamon

    (Publisher)

  Regional Differences in Primary Production A world map of primary production, based mainly on 1 4 C determinations, such as that prepared by Koblentz-Mishke, Volkovinsky and Kabanova (1970), with slight modifications by Parsons and Takahashi (1973a), is remarkably similar to maps of standing phytoplankton crop (cf. Fig. 9.3). In general, productivity in warm oceans, especially in the centre of major gyres, is low, apart from areas of upwelling and 90° P r i m a r y p r o d u c t i o n ( m g C / m2 / day) 180° o e 180° 90° < 100 100 -150 I 1 5 0 -2 5 0 HISSÉ > 2 50 Fig. 9.3. Distribution of primary production in the World Ocean (after Parsons and Takahashi, 1973, redrawn from Koblentz-Mishke et al. y 1970). Primary Production: Global Considerations 405 divergences, and is subject to relatively small and often irregular fluctuations over the year. By contrast, seas at moderately high latitudes may show a much higher level of primary production, though this is strongly influenced by pronounced seasonal fluctu-ation. Areas near coasts also are marked by increased productivity (cf. Fig. 9.3). A more detailed analysis of spatial and temporal variations in primary production is now required. 1. Tropical and sub-tropical seas Smayda (1963, 1965, 1966) has carried out one of the few detailed investigations of primary production over a considerable period of time in a tropical area. Working in the Gulf of Panama, he found seasonal and monthly variations in carbon assimilation (see Fig. 9.4) which generally paralleled standing-crop fluctuations. The area is characterized by considerable seasonal change; off-shore winds cause marked upwelling approximately over the period January to April. During this time, colder saline and nutrient-rich water comes towards the surface. By contrast, during the summer and autumn months a rainy period intervenes with considerable run-off from the land.

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  Ecology of Tropical Oceans

  • Bozzano G Luisa(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  Only in special cases, where some surface species (bigeye tuna, sperm whales) are involved, is there active transport of energy vertically upward by the feeding excursions of larger biota. Figure 5.6 illustrates the variability in primary production in open-ocean ecosystems of the kind we describe here for the eastern tropical Pacific: Most of the area produces <200-300 mgC m~ 2 d 1 , with regions of equatorial and coastal divergence (where new production is important) rising to >500 mgC m~ 2 d _ l . Zooplankton grazing is in approximate bal-ance with organic production in the open ocean, for grazing pressure not only co-occurs in the vertical plane with plant production, but over large areas of the tropical ocean, as we have noted above, there is a linear relationship between zooplankton and plant biomass per unit area (Le-Borgne et al., 1983). Ecosystem Trophodynamics: Open Oceans 123 Given the range of mechanisms by which new production may be fu-elled in the open ocean, it is not surprising that integrations of autotrophic production and heterotrophic consumption demonstrate a wide range of differently balanced budgets. However, in tropical oceans it is not usual to find production greatly in excess of consumption as frequently occurs in high latitude spring bloom situations, or in pulsed coastal upwelling ecosystem; indeed, some models, such as some of those proposed by Sorokin et al. (1985) for the Indian Ocean, appear to confirm that rela-tively few plant cells are lost to the epipelagic ecosystem of the oligo-trophic ocean by sinking before they are consumed by herbivores. Where dynamic processes disturb this equilibrium, and cause nitrate and other inorganic nutrients to be transported up into the euphotic zone, new production is intensified and the area supports larger standing stocks of pyto- and zooplankton than surrounding regions.

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  Tropical Marine Ecology

  • Daniel M. Alongi(Author)
  • 2021(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  2008 ). Thus, there should also be a component of enhanced production due to enhanced nutrient flux to the euphotic zone. That is, the very intense upwelling at the trailing edge of the cool SST anomaly entrains subsurface nutrients into the euphotic zone and stimulates phytoplankton growth, greater than in the existing bloom conditions of the equatorial upwelling tongue.

  FIGURE 8.9

  Satellite image of the global distribution of annual marine net primary productivity (mg C m−2 d−1 ), 2017, based on the updated cbpm algorithm from VIIRS (GSM) data, prepared by Oregon State University. Monthly files have been averaged.

  Source: Image produced by Hugo Ahlenius and used with permission from Nordpil (acquired 18 June 2018). © Nordpil.

  Primary productivity thus varies greatly temporally and spatially depending upon complex physical and chemical gradients. Tropical intra‐seasonal variability is an important process, and a notable form of such variability is the MJO (Section 2.6 ), which is characterized by large‐scale eastward‐propagating disturbances in the tropics. The MJO produces systematic and significant variations in ocean surface chlorophyll (and likely primary productivity) in several regions across the tropical Pacific and Indian Oceans, including the northern Indian Ocean, a broad expanse of the NW tropical Pacific Ocean, and several near‐coastal areas in the far eastern Pacific Ocean (Chang et al. 2019 ). Wind‐induced vertical entrainment at the base of the ocean mixed layer appears to play an important role in modulating ocean chlorophyll.

  In the tropical Atlantic, primary productivity may be P and N limited; nitrogen fixation may in turn be limited by atmospheric deposition of Fe (Chien et al. 2016 ). Nutrient fluxes are highest in the eastern tropical Atlantic owing to the proximity of West Africa and Europe and lowest in the western tropical Atlantic (Baker et al. 2007 ). Phytoplankton biomass and production across the eastern tropical Atlantic appear to be driven by major changes in nutrient supply across the thermocline, which average 0.99 mmol N m−2 d−1 and 0.13 mmol P m−2 d−1 and are particularly high in the upwelling area off NW Africa. From 2° N to 5° S, the equatorial divergence results in a shallowing of the pycnocline and the presence of relatively high NO3 ‐ concentrations in surface waters. Primary production can vary from about 200 mg C m−2 d−1 in less productive, subtropical gyres to about 1300 mg C m−2 d−1 in the equatorial divergence area (Pérez et al. 2005 ). Because of the relatively high primary production rates in the equatorial upwelling region, only a moderate rise in phytoplankton biomass occurs as compared to nearby nutrient‐depleted areas. Picophytoplankton are the main contributors (>60%) to both biomass and production in this region. Equatorial upwelling does not alter the phytoplankton size structure typically found in the tropical open ocean, which suggests a strong top‐down control of primary producers by zooplankton. The entire region shows net autotrophic community metabolism since respiration accounts for only about half of GPP in the euphotic zone. Below the euphotic zone lies a moderate OMZ; mesoscale eddies with close to anoxic oxygen concentrations are located just below the mixed layer. In these eddies, primary productivity is enhanced, and carbon uptake rates are up to 3× higher than in surrounding waters. Carbon uptake rates below the euphotic zone correlates with the presence of Prochlorococcus. The high primary productivity fuels export of production and supports enhanced respiration below the mixed layer (Löscher et al. 2015

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  Elements of Marine Ecology

  An Introductory Course

  • R. V. Tait(Author)
  • 2013(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  Organic production in the sea The organic food cycle The synthesis of organic compounds from the inorganic constituents of seawater by the activity of organisms is termed production. It is effected almost entirely by the photosynthetic activity of marine plants, with traces of organic matter also formed by chemosynthesis. The raw materials are water, carbon dioxide and various other substances, the nutrients, mainly inorganic ions, principally nitrate and phosphate. Chlorophyll-containing plants, by making use of light energy, are able to combine these simple substances to synthesize complex organic molecules. This is termed Gross Primary Production. The chief products are the three major categories of food materials, namely carbohydrates, proteins and fats 3 6 . Some of the organic material manufactured by plants is broken down again to inorganic state by the plants themselves in the course of their respiration. The remainder is referred to as Net Primary Production and much of this becomes new plant tissue. This is of major importance as the source of food for herbivorous animals. Upon the Net Primary Production therefore depends, directly or indirectly, the animal population of the sea. By far the greater part of Primary Production in the sea is performed by the phytoplankton. Under favourable conditions this is capable of remarkably rapid growth, sometimes producing its own weight of new organic material within 24 hours, a rate greater than that achievable by land plants. The large marine algae growing on the sea bottom in shallow water make only a relatively small contribution to the total production in the sea because they are of very restricted distribution. The consumption of plants by herbivorous animals leads to the formation of animal tissue. This is Secondary Production, which in turn becomes food for the first rank of carnivorous animals (Tertiary production), and these may then fall prey to other carnivores, and so on (Figure 5.1).

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  Economics in Commercial Fisheries

  • Biswas, K P(Authors)
  • 2021(Publication Date)
  • Daya Publishing House

    (Publisher)

  This ebook is exclusively for this university only. Cannot be resold/distributed. In 1996, FAO published a chronicle of global fisheries showing that a rapidly increasing fraction of world catches originate from stocks that are depleted or collapsed. But misreporting of catch data by countries with large fisheries, combined with the large and widely fluctuating catch of the species, like Peruvian anchoveta can cause globally spurious trends. Such trends influence unwise investment decisions by firms in the fishing sector and by banks and prevent the effective management of international fisheries. Trends in Marine Fish Catch Oceanic Regime Out of a total ocean surface of about 360 million square kilometer the neritic environment over the continental shelves covers almost 32 million square kilometer and hence the oceanic region accounts for over 91 per cent of the world oceans. Although mean productivity per unit area is much lower in the oceans than on land, their very large surface means that the oceans still account for at least a third of the annual global carbon fixation. For this reason, oceanic communities contribute significantly to global process. Oceanic phytoplankton is responsible for the primary production of the oceans and constitute the basis of the food chain in the high seas. Primary production is restricted to the so-called euphotic layer or upper part of the photic zone, where sufficient sunlight penetrates to allow photosynthesis. The depth of the euphotic zone depends on the amount of suspension and detritus present in the water and can vary from 40-50 m. in turbid waters to over 100 m. where the waters are particularly clear. Production is also limited by the availability of inorganic nutrients. Below the photic layer there is the aphotic zone, where no light arrives and primary production is absent.

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  Marine Interfaces Ecohydrodynamics

  • J.C.J. Nihoul(Author)
  • 1986(Publication Date)
  • Elsevier Science

    (Publisher)

  Biological production has been defined above as the flow of primary energy into a given trophic level. High specific production indicates that the high biological production measured a t sea results from enhanced biological transfer of primary energy and not only from high accumulated biomass. If the hypothesis of independence i s rejected, 21 the spatio-temporal zone o f high biological production most l i k e l y corresponds t o an ergocline, as a l l ergoclines have the common characteristic o f involving spatial and/or temporal gradients where physical processes can produce structures associated with enhanced biological production (see above). The general ergocline hypothesis can be further investigated by testing t h i s next hypothesis: A t ergoclines, the temporal, horizontal o r vertical d i s t r i b u t i o n o f physical scales does not necessarily correspond t o the characteristic scales o f biological production. I n order t o try f a l s i f y i n g t h i s second hypothesis, one must (1) determine the characteristic time and space scales o f biological production a t the ergocline (e.g. Table 2) and (2) compare the d i s t r i b u t i o n o f the physical scales associated with the ergocline t o these characteristic biological scales. If dominant physical scales a t the ergocline (which i s the spatio-temporal zone o f enhanced biological production) do coincide with the characteristic biological scales, the second hypothesis can be rejected and the implications o f the ergocline hypothesis can be further explored. The f i r s t interesting question raised by the ergoclines hypothesis concerns the mechanisms through which biological production increases a t ergoclines.

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  Ecological Geography of the Sea

  • Alan R. Longhurst(Author)
  • 2010(Publication Date)
  • Academic Press

    (Publisher)

  It is also very easy to interpret a change in the sign of biomass change as necessarily reflecting a similar change in sign of the production rate. None of which, as we should know, is necessarily so. One of the earliest findings in the study of plankton dynamics was that even large diatoms can be consumed almost as rapidly as they are produced. In 1935, Harvey and others thought that 98% of the production in the English Channel of the spring bloom was grazed down by copepods in a few weeks, and later workers, who included Fleming, Riley, Gauld, and Cushing, reached similar conclusions for coastal waters. By 1942, Hart had extended such calculations to the Southern Ocean, where he found that the stand-ing stock of phytoplankton represented only about 2% of its daily production. From these early observations, the dynamic balance between production and disappearance of phytoplankton cells should subsequently have been the central theme of biological oceanography but, as Banse (1992) pointed out, this has, most disconcertingly in retro-spect, not been the case. Perhaps, he suggests, because of the difficulty of research on consumers (great functional diversity and dimensional range) and the easier access to simple demonstration of biological principles in phytoplankton research, teachers have given priority to the latter: consequently, research on production and consumption has been only very loosely coupled. So it may be instructive to ask what satellite imagery can tell us about the dynamics of algal blooms. 12 Chapter 1: Toward an Ecological Geography of the Sea For each province subsequently to be described and for each month, we have mean values that specify surface chlorophyll, integrated chlorophyll, and integrated primary production rate. By comparing rates of actual and potential increase of phytoplankton from these, it is simple to propose a first-order plankton calendar for each province that integrates both production and loss of cells.

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  Polar Research

  To The Present, And The Future

  • Mary A. Mcwhinnie(Author)
  • 2019(Publication Date)
  • Taylor & Francis

    (Publisher)

  6 Primary Productivity and Estimates of Potential Yields of the Southern Ocean Sayed Z. El-Sayed

  I. Introduction

  Interest in the biological productivity of the Southern Ocean dates back to Captain James Cook's second voyage of discovery (1772-75). In his account he drew attention to the productivity of these southern waters. The richness of the Antarctic seas in plant and animal life has been recognized during the EREBUS and TERROR expedition (1839-43), under James Clark Ross. During this expedition J. D. Hooker, the famed botanistsurgeon, collected plankton samples and sent them to Ehrenberg, who in 1844 published the first paper on Antarctic diatoms. Durmont D'Urville in his "Voyage au Pole Sud et dans l'Oceanie" published in 1845, also wrote an interesting account of the richness of the Antarctic waters.

  In the following one hundred years the data from the numerous Antarctic expeditions served to perpetuate the belief in the extreme richness of the Antarctic seas. The enormous catches of baleen whales taken from these waters, together with the teeming of the coastal waters with seals, winged birds and penguins, lend support to this belief. The initiation of the DISCOVERY investigations (1925-39) laid the foundation of our knowledge of the general oceanography of the Southern Ocean. These investigations contributed substantially to our understanding of the distribution and abundance of phytoplankton, zooplankton (with special emphasis on krill, Euphausia superba ) fish and whales. However, it was not until the early 1960's (with the use of the radioactive carbon-14 method in primary productivity measurements) that the first direct estimates of primary productivity of the Antarctic seas were obtained (Klyashtorin, 1961; Ichimura and Fukushima, 1963; El-Sayed, Mandelli and Sugimura, 1964; Saijo and Kawashima, 1964; Volkovinsky, 1966).

  Thanks to the extensive cruises of the USNS ELTANIN, the U.S.S.R. OB and other research vessels in the 60's and early 70's, sufficient data on primary production have now accumulated to allow estimates of the productivity of the Southern Ocean (Mandelli and Burkholder, 1966; El-Sayed, 1967, 1968a,b; El-Sayed and Jitts, 1973; El-Sayed and Turner, in press; Holm-Hansen, El-Sayed, Franceschini and Cuhel, in press). These estimates, which are largely based on station data taken by oceanographic ships at different times and often in different years, vary widely. The estimates clearly reflect the great variability in the productivity values obtained in the circum-Antarctic waters. They also pointed to the marked differences between the more productive coastal regions and the poorer oceanic waters (El-Sayed, 1970).

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