H.J. Minas

Université de Bretagne Occidentale, Brest, Brittany, France

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Publications (33)28.69 Total impact

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    ABSTRACT: Thirty years of data were used to examine the influence of the Rhône River discharge on the spatio-temporal distribution of primary production in the Gulf of Lions. These patterns are characterised for four hydrological provinces: (i) the Gulf of Marseilles, a coastal oligotrophic system exhibiting a typical diatom-based bloom succession; (ii) the mouth and plume of the Rhône River, containing high levels of nutrients, constant levels of chlorophyll a, and a plankton assemblage dominated by nanoflagellates; (iii) the highly productive dilution area to the west of the Rhône, with a diatom spring bloom and smaller winter diatom blooms; (iv) the southern area encompassing the oligotrophic Liguro-Provençal Current, a frontal zone of constantly high primary production and a divergence area exhibiting a typical spring bloom situation.No evidence of eutrophication due to river input was seen. In situ and in vitro net community production data suggest the Gulf of Lions as a whole is a balanced ecosystem on an annual time scale, with the mean primary production lying between 78 and 142 g C m−2 a−1.
    Full-text · Article · Dec 1997 · Deep Sea Research Part II Topical Studies in Oceanography
  • H.J. Minas · M. Minas
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    ABSTRACT: Atlantic waters feed the Mediterranean Sea and are therefore responsible for the general oligotrophic and relatively well oxygenated regime. The outflowing Mediterranean waters are nutrient-enriched and show the effect of mineralization. The piers supporting a prospective Gibraltar bridge may induce certain hydrological and biological consequences. -from English summary
    No preview · Article · Jan 1993
  • H.J. Minas · M. Minas
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    ABSTRACT: Grazing appears to be the main factor responsible for lowering the rate of increse, especially in moderate and strong High Nutrient-Low Chlorophyll (HNLC) waters. A simple model comparing Net Community Production (NCP) rates with observed chlorophyll increase rates suggests that phytoplankton population must present high specific growth rates on a daily rhythm in order to overcome grazing. Maximum specific growth rates (Vmax) calculated for daily total production (TP) are, in the two main upwelling areas, 1.57 d-1 off NW Africa and 1.04 d-1 off Peru. For extreme HNLC conditions in the Costa Rica Dome, Vmax remains high, 0.98 d-1. The Atlantic equatorial upwelling in the Gulf of Guinea is characterized by moderate HNLC conditions. From an analysis of a nutrient-temperature diagram and heat fluxes, the authors deduce a nitrate-based new production (NP) rate of 0.368 g C m-2 d-1. The Peruvian coastal upwelling, during the strongest upwelling period in austral winter, shows HNLC conditions extending far offshore and reaching the Galapagos Islands. NCP could not be determined in these waters. Antarctic nutrient consumption diagrams are also presented. From the end of winter to end of summer, the average nitrate consumption is 0.38 mol m-2. For the five month period, the calculated NP is 0.2 g C m-2 d-1. The model application leads to a Vmax (TP) value of 0.54 d-1, which does not seem excessively low in the low temperature regime of the Southern Ocean. Despite evidence in favour of the grazing hypothesis which allows the authors to classify regions geographically into "high and low' speed areas of phytoplankton development, a global chart of dust inputs into the ocean strongly supports the iron limitation hypothesis. -from Authors
    No preview · Article · Jan 1992
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    ABSTRACT: Previous hydrological investigations of the Gibraltar Strait have left some questions unanswered as regards the composition of the Mediterranean outflow into the Atlantic Ocean. In the present study, nutrient, oxygen, and chlorophyll distributions are used to characterize the main water masses flowing through the Strait of Gibraltar and the Alboran Sea, with particular reference to Levantine Intermediate Water (LIW) and Western Mediterranean Deep Water (WMDW). High chlorophyll a concentrations, reaching 3 mug L-1 at the subsurface, are observed in the northern part of the anticyclonic Alboran Sea gyre. The salinity subsurface minimum (~=36), located temporarily in the strait, corresponds to high nutrient concentrations (7-8 mug at. L-1). Diagram analysis shows that in the upwelling area off the Spanish coast, nutrients are largely transported into the photic zone, and that photosynthetic nitrate consumption actually takes place. Consequently, the formation of the Alboran Sea O2 extraminimum can be related to the enhanced new production. Most of the lowest O2 values (
    No preview · Article · May 1991 · Journal of Geophysical Research Atmospheres

  • No preview · Article · Jan 1989 · Global Biogeochemical Cycles
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    ABSTRACT: The enhanced oxygen minimum in the western Alboran Sea is the result of a chain of processes starting with nutrient injection into the inflowing Atlantic water at the Strait of Gibraltar. These nutrients originate in the outflowing Levantine Intermediate Water, outflowing Mediterranean deep water, and inflowing North Atlantic Central Water (from 200 m). They are injected into the inflowing Atlantic surface water by strong mixing at the eastern end of the Strait. They move with Atlantic surface waters along the Spanish coast, mix with nutrients upwelling in the northwestern Alboran Sea and stimulate phytoplankton productivity. The organic matter produced by this mechanism is transported both with the anticyclonically flowing waters of the Alboran gyre and with the waters that converge at the center of the gyre. Sedimentation in this convergence zone helps to deliver this organic matter to the Levantine Intermediate. Water where bacteria metabolize it to CO2 at the expense of the existing oxygen. This mechanism develops the most intense oxygen minimum zone in the Mediterranean Sea.
    Full-text · Article · Jul 1988 · Deep Sea Research Part A Oceanographic Research Papers
  • Bernard Coste · Pierre Le Corre · Hans Joachim Minas
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    ABSTRACT: New data of inorganic, particulate and dissolved organic forms of nitrogen, phosphorus and silicon from the Mediterranean Sea near the Strait of Gibraltar allow an estimate of the exchanges of these elements between the Mediterranean Sea and the Atlantic Ocean. Input by Atlantic waters is lower than output by the Mediterranean waters. The difference accounts for about 10% of the total nitrogen and phosphorus outflow and for about 50% of the total silicon outflow. The deficit appears to be balanced by the nutrient supply from land drainage. The dissolved organic nitrogen and phosphorus are about 50% of the total nitrogen and phosphorus inflow and less than 30% of the outflow. The Mediterranean Sea appears to be an active basin of mineralization.
    No preview · Article · May 1988 · Deep Sea Research Part A Oceanographic Research Papers
  • Source
    Coste B. · Le Corre P. · Minas H.J. · Morin P.

    Full-text · Article · Jan 1988 · Oceanologica Acta
  • Source
    HANS JOACHIM MINAS · MONIQUE MINAS · THEODORE TRAIN PACKARD
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    ABSTRACT: A combination of Broenkow's nutrient oxygen model and Bowden's residence time evaluation of upwelled waters enabled us to calculate the "net community production" (NCP) in coastal upwelling areas (NW Africa, SW Africa, Peru) and in an open upwelling (Costa Rica Dome). Since NCP represents mainly new production in terms of phosphorus or nitrogen, and since it derives from integrated nutrient consumption over the main production area, a good picture of the average fertility of these zones is obtained. In terms of carbon, NCP averaged 0.6 g C m-2 d-l off Peru, 1.1 off SW Africa, and 2.3 off NW Africa. However, production budget per kilometer of coastline is greater for both Peru and SW Africa than it is for NW Africa. The lower activities off Peru and off SW Africa correspond to a relatively high nutrient-low chlorophyll (HNLC) situation, char- acterized by a slowly growing phytoplankton standing stock. Such HNLC situations are greatly pronounced in the Costa Rica Dome, with NCP values as low as 0.14 g C m-2 d-l. Herbivorous grazing in the freshly upwelled source water appears to be the most plausible explanation for the low chlorophyll. This mechanism for cropping phytoplankton and retarding nutrient uptake pro- vides a way to spread nutrient input to the open ocean. Italso explains the prevalence of oxygen undersaturation (and CO, oversaturation) in the surface waters of the equatorial upwelling. By using the NW African data and NCP and ammonium excretion rates from the literature we could calculate an Eppley ffactor (pN0, - : pNO,- f pNH,+) of 0.64. *
    Full-text · Article · Jan 1986 · Limnology and Oceanography
  • H.J. Minas · M. Minas · T.T. Packard
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    ABSTRACT: A combination of Broenkow's nutrient oxygen model and Bowden's residence time evaluation of upwelled waters enabled calculation of the 'net community production' (NCP) in coastal upwelling areas (NW Africa, SW Africa, Peru) and in an open upwelling (Costa Rica Dome). Since NCP represents mainly new production in terms of P or N, and since it derives from integrated nutrient consumption over the main production area, a good picture of the average fertility of these zones is obtained. In terms of carbon, NCP averaged 0.6 g C m-2 d-1 off Peru, 1.1 off SW Africa, and 2.3 off NW Africa. However, production budget per kilometer of coastline is greater for both Peru and SW Africa than it is for NW Africa. The lower activities off Peru and off SW Africa correspond to a relatively high nutrient-low chlorophyll (HNLC) situation, characterized by a slowly growing phytoplankton standing stock. Such HNLC situations are greatly pronounced in the Costa Rica Dome, with NCP values as low as 0.14 g C m-2d-1. Herbivorous grazing in the freshly upwelled source water appears to be the most plausible explanation for the low chlorophyll. This mechanism for cropping phytoplankton and retarding nutrient uptake provides a way to spread nutrient input to the open ocean. It also explains the prevalence of oxygen undersaturation (and CO2 oversaturation) in the surface waters of the equatorial upwelling.-from Authors
    No preview · Article · Jan 1986
  • Chapter: Respiration
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    ABSTRACT: The respiration working group conducted nine discussions. Each was led by a working group member after presenting his recent ideas and results. The discussions focused on topics that facilitated achieving the following objectives: 1. to develop a fundamental definition of respiration that is accurate and descriptive at all levels of biological organization. 2. to review the limitations and strengths of current methods of measuring respiration. 3. to identify areas for the potential application of new technology. 4. to identify “user interest” in respiration measurements (i.e., the modeling community) and how dimensions, time-scale, and space -scale effects the “usefulness” of a respiration measurement. 5. to determine the feasibility of developing a unifying model of respiration that can be applied to different organisms, communities, and ecosystems. 6. to assess the compatibility of the results of respiration studies with the results of other process studies. 7. to summarize the state of knowledge of respiration, to identify the limitations of that knowledge, and to recommend research for the next decade.
    No preview · Chapter · Jan 1984
  • Minas H · Coste B · Minas M
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    ABSTRACT: Satellite infrared imagery shows that a cooling of the sea furface occurs in the Strait of Gibraltar and along the Spanish coast in the Alboran Sea. Since this cooling has an internal origin, it implicates also a nutrient transport into the photic zone. A high chlorophyll area off the Spanish coast, also shown by ocean color imagery (CZCS, Nimbus 7) demonstrate a high productivity. Hydrological and chemical observations made during the French "MEDIPROD IV" cruise on the Jean-Charcot allow to explain this high productivity. The high productivity entertains at mid-depth, by organic sedimentation, an oxygen minimum layer which corresponds to a nutrient maximum (phosphate and nitrate). This high biological activity is useful for hydrological purposes since the tracer qualities of biochemical parameters lead to a better understanding of the circulation pattern and especially of the origin of the Mediterranean outflow.
    No preview · Article · Jan 1984
  • Source
    Minas H · Minas M · Packard T
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    ABSTRACT: When in frontal zones of upwelling areas, a two-component mixing of nutrient rich upwelled water and oligotrophic offshore waters occurs, the amounts of nutrient consumed (- Delta N) and oxygen produced (+ Delta O2) can be evaluated by a detailed analysis of diagrams, in which salinity is the conservative parameter. By this same method, the corresponding T-S diagram allows a determination of the net heat gain of the upwelling water body during its offshore transport, and consequently the corresponding residence time in the photic zone. By integrating the nutrient consumption over the whole upwelling area, it is possible to obtain a more realistic average value of the productivity than with direct measurements of photosynthetic activity (14C and other incubation methods). The Pacific Ocean upwellings are richer, and within the Atlantic Ocean, the nutrient richer SACW in regard to the NACW (south and North Atlantic Central Waters) explains greater carbon budgets in the concerned upwelling zones.
    Full-text · Article · Jan 1984
  • Source
    HJ Minas · TT Packard · M Minas · B Coste
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    ABSTRACT: The ratio of nitrogen decrease to oxygen increase in the photic zone is nearly identical to the Redfield ratio of 5.18 mu g-at N/ml O2. In addition to its close couple with nitrate uptake, the oxygen increased directly with the chlorophyll in the offshore-moving waters. -from Authors
    Full-text · Article · Jan 1982
  • TT Packard · HJ Minas · T Owens · A Devol

    No preview · Article · Jan 1977
  • Gerd Slawyk · Hans Joachim Minas · Monique Minas · Theodore T. Packard
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    ABSTRACT: The present investigation re-examines hydrological features, the inorganic phosphate distribution and primary productivity near the “Hyères” Islands in the French Mediterranean in the early summer divergence zone as previously studied by MINAS and BLANC (1970). In addition, concentrations of particulate nitrogen, Chl-a and nitrate have been determined. Uptake rates of 15N-labelled nitrate (“new production”) and the oxygen consumption (ETS-activity) by the phytoplankton population have been estimated.
    No preview · Article · Jan 1976 · Internationale Revue der gesamten Hydrobiologie und Hydrographie
  • P. L. Laborde · H. J. Minas
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    ABSTRACT: Vertical distribution of daily primary production rates and adenosine triphosphate (ATP) concentrations were observed during two periods (7–17 March, and 4–14 April, 1969), at a fixed station in the northern Mediterranean Sea (CNEXO Laboratory Buoy). The ATP values and the 14C-uptake rates increased daily during the two observation periods; this increase is compared to variations in hydrological conditions. Vertical profiles of both photosynthetic activity and biomass (ATP) revealed a subsuperficial maximum. The ATP maximum is usually below the photosynthetic maximum, especially when the values of both parameters are high. The probable origin of the ATP maximum and its relation to the production maximum are discussed. A conversion of the ATP values in terms of chlorophyll a, on the basis of 1 mg ATP=250 mgC and 1 mg chlorophyll a=60 mgC, leads to relatively high values of the productivity index (2.4 to 14 mgC·mgChl a -1·h-1).
    No preview · Article · Jan 1974 · Marine Biology
  • Minas H J · Romana LA · Packard TT · Bonin MC

    No preview · Article · Jan 1974
  • B. Berland · D. Bonin · B. Coste · S. Maestrini · H. J. Minas
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    ABSTRACT: Bioassays were performed on surface-water samples, collected during the Médiprod I cruise of the R.V. “Jean Charcot” in the northern part of the Mediterranean Sea. Physiological responses of axenic algal cultures were measured in order to characterize the different water masses. The responses obtained are specific to each algal strain: Phaeodactylum tricornutum grows in all waters sampled during the first part of the cruise, while Chaetoceros lauderi does not develop because of its different nutritional requirements; Chlamydomonas magnusii does not grow in any of the tested samples. No clear relationship exists between the results obtained in vitro and those obtained in situ but, on the whole, the waters collected during the second part of the cruise allow a higher growth of the test algae in vitro. This higher fertility is probably related to the algal bloom which occurred between the first and the second part of the cruise. In the authors' opinion the great difference in uptake rates observed between the high-turbulence area (low production) and the adjacent area (high production), may be related more to biological conditioning than to any physical process. However, physical mixing seems to be responsible for inhibition of primary productivity at the two stations where mixing attains maximum values.
    No preview · Article · Nov 1973 · Marine Biology
  • G. Jacques · H. J. Minas · M. Minas · P. Nival
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    ABSTRACT: 1.1. En mars, durant la mission Mdiprod I du Jean Charcot, les conditions hydrologiques sont caractrises par un mlange vertical avec transport des sels nutritifs vers la couche euphotique. Entre cette zone de mlange et la bordure priphrique oligotrophe, on trouve une rgion o la prsence simultane de sels nutritifs et de stabilit cre des conditions favorables une pousse planctonique.En mars, durant la mission Mdiprod I du Jean Charcot, les conditions hydrologiques sont caractrises par un mlange vertical avec transport des sels nutritifs vers la couche euphotique. Entre cette zone de mlange et la bordure priphrique oligotrophe, on trouve une rgion o la prsence simultane de sels nutritifs et de stabilit cre des conditions favorables une pousse planctonique. 2.2. En avril, la stabilisation par rchauffement permet une lvation gnrale des biomasses, particulirement au large o le mlange vertical fut intense.En avril, la stabilisation par rchauffement permet une lvation gnrale des biomasses, particulirement au large o le mlange vertical fut intense. 3.3. Les taux de production atteignent 2 gCm-2. jour-1 et la chlorophylle a dpasse 3 mgm-3. Ces valeurs leves pour une rgion rpute oligotrophe sont pourtant conformes la fertilit potentielle tablie sur la teneur en sels nutritifs.Les taux de production atteignent 2 gCm-2. jour-1 et la chlorophylle a dpasse 3 mgm-3. Ces valeurs leves pour une rgion rpute oligotrophe sont pourtant conformes la fertilit potentielle tablie sur la teneur en sels nutritifs. 4.4. Des conditions de stabilit suffisantes pour le dveloppement du phytoplancton sont cres soit par intrusion d'une eau riche en sels nutritifs dans un systme oligotrophe stratifi (pousse hivernale), soit par stratification thermique d'une eau de mlange (pousse printanire).Des conditions de stabilit suffisantes pour le dveloppement du phytoplancton sont cres soit par intrusion d'une eau riche en sels nutritifs dans un systme oligotrophe stratifi (pousse hivernale), soit par stratification thermique d'une eau de mlange (pousse printanire). 5.5. Le long des ctes, la salinit faible empche les mlanges; la situation est constamment oligotrophe.Le long des ctes, la salinit faible empche les mlanges; la situation est constamment oligotrophe. 6.6. Biomasse et production sont du mme ordre de grandeur dans la rgion provenale et dans la rgion Cte d'Azur pourtant moins expose aux conditions rigoureuses. Dans cette dernire zone, l'apport nutritif par intrusion d'eau intermdiaire joue un rle important alors que le mlange vertical est la base de la fertilisation dans la rgion provenale.Biomasse et production sont du mme ordre de grandeur dans la rgion provenale et dans la rgion Cte d'Azur pourtant moins expose aux conditions rigoureuses. Dans cette dernire zone, l'apport nutritif par intrusion d'eau intermdiaire joue un rle important alors que le mlange vertical est la base de la fertilisation dans la rgion provenale. Hydrological observations, and measurements of nutrient chemistry, plankton biomass, and production were carried out during the Mdiprod I cruise of the R.V. Jean-Charcot. The March cruise was characterized by almost winter conditions, exhibiting strong vertical mixing of water masses in the offshore region and nutrient transport up to the photic zone. According to the working hypothesis, the strong vertically mixed area (e.g. Station 15) and the surrounding oligotrophic area are separated by an intermediate zone, where both nutrients and stability have produced phytoplankton-bloom conditions. During the April cruise, highest biomass and production rates were encountered everywhere in the offshore region, and especially in the previously mixed area of central divergence. Production was as high as 2 gCm-2 day-1, and the standing crop of chlorophyll was 3 mgm-3; such values are rather important for the so called poor Mediterranean Sea. Salinity-phosphate and chlorophyll-phosphate diagrams are presented. Biomass and production rates are in agreement with the potential fertility based on the nutrient content of the waters. The disappearance of 1 atg PPO4 by photosynthetic uptake corresponds to 7.7 mg chlorophyll a, which represents the autotrophic biomass remaining after grazing by the simultaneous zooplankton bloom. Biomass and production features are analyzed in regard to interaction of both nutrient availability and the stability of water masses. Stability conditions can be created either by intrusion of local mixing in a stratified oligotrophic area (winter bloom), or by thermal stratification of the upper layer (spring bloom). In the latter case, the highest biomasses are present in the zone where the nutrients were previously introduced by mixing. The oligotrophic situation remained constant during the two crunises in the surrounding coastal area, which is characterized by low-salinity water and, therefore, absence of vertical nutrient transport into the photic zone. Chlorophyll pigment concentration and photosynthetic rates in the Cote d'Azur region are similar to those in the Provence region; this situation may result more from upwelling of nutrient-rich intermediate water than from the mixing process which predominates in the latter region.
    No preview · Article · Nov 1973 · Marine Biology

Publication Stats

813 Citations
28.69 Total Impact Points

Institutions

  • 1991
    • Université de Bretagne Occidentale
      • Département de Chimie
      Brest, Brittany, France
  • 1988
    • Centre d'Immunologie de Marseille-Luminy
      Marsiglia, Provence-Alpes-Côte d'Azur, France
  • 1976
    • University of Washington Seattle
      • School of Oceanography
      Seattle, Washington, United States