P limitation of heterotrophic bacteria and phytoplankton in the northwest Mediterranean

Thingstad, T. Frede; Zweifel, Ulla Li; Rassoulzadegan, Fereidoun

doi:10.4319/lo.1998.43.1.0088

Cited by 343 publications

(281 citation statements)

References 26 publications

(28 reference statements)

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“…In contrast, phytoplankton are expected to sequester an increasing fraction of available nutrients with increasing trophic state as a result of their larger cell size (Cotner and Biddanda 2002). Several studies have demonstrated that the ability of phytoplankton to take up P and accumulate higher intercellular P levels is either comparable (Vadstein et al 1989) or superior to the ability of bacteria (Suttle et al 1990;Cotner and Wetzel 1992;Thingstad et al 1993).…”

Section: Resultsmentioning

confidence: 99%

Nutrient and light availability regulate the relative contribution of autotrophs and heterotrophs to respiration in freshwater pelagic ecosystems

Roberts

Howarth

2006

Limnol. Oceanogr.

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In this study, two main hypotheses were addressed. (1) Bacteria contribute proportionally less than autotrophs to ecosystem respiration as trophic status increases. This hypothesis was examined in a pond phosphorus-fertilization experiment and two microcosm nutrient-fertilization experiments. (2) The relative contribution of autotrophs to ecosystem respiration, at a given nutrient availability, increases as light availability increases. This hypothesis was tested in three light by nutrient factorial microcosm experiments. Rates of total plankton community, bacterial (Ͻ1 m fraction), and phytoplankton (total Ϫ bacterial) respiration all increased as nutrient availability increased. The contribution of bacteria to community respiration ranged between ϳ10 and 90%, with the highest contribution occurring under the most oligotrophic conditions. As light availability increased within each nutrient availability treatment, there was a similar decline in the contribution of bacteria to community respiration. Under oligotrophic conditions bacteria are better competitors for nutrients that limit both autotrophs and heterotrophs, but as nutrient availability increases, conditions become increasingly favorable for larger celled phytoplankton that have higher maximal nutrient uptake rates. As light availability increases, the relative contribution of phytoplankton to ecosystem respiration also increases. Light and nutrient availability are important regulators of the relative contributions of autotrophs and heterotrophs to ecosystem respiration, but the observed patterns are primarily driven by changes in phytoplankton production rates.

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Section: Resultsmentioning

confidence: 99%

Nutrient and light availability regulate the relative contribution of autotrophs and heterotrophs to respiration in freshwater pelagic ecosystems

Roberts

Howarth

2006

Limnol. Oceanogr.

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“…In the Mediterranean Sea, which is one of the world's most oligotrophic bodies of water, inorganic nutrients and particularly phosphate (P) have been shown to limit both phytoplankton and bacteria in certain areas during stratification (Pinhassi et al, 2006;Thingstad et al, 1998;Van Wambeke et al, 2002). Despite unusual high phosphate concentrations at station C, in situ chemical concentrations indicated more stringent oligotrophic conditions in the eastern basin than in the western basin .…”

Section: Bacterial Productionmentioning

confidence: 98%

Ecology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

et al. 2011

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Abstract. Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a) and AAP bacterial abundance decreased from the western to the eastern basin of the Mediterranean Sea and were linked with concentrations of chlorophyll-a, nutrient and dissolved organic carbon. Inorganic nutrient and glucose additions to surface seawater samples along the oligotrophic gradient revealed that AAP bacteria were nitrogen-and carbon-limited in the ultraoligotrophic eastern basin. The intensity of the Correspondence to: D. Lamy (lamyd2@univie.ac.at) AAP bacterial growth response generally differed from that of the total bacterial growth response. BChl-a quota of AAP bacterial communities was significantly higher in the eastern basin than in the western basin, suggesting that reliance on phototrophy varied along the oligotrophic gradient and that nutrient and/or carbon limitation favors BChl-a synthesis.

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“…9,43,44 A unique characteristic of the water masses of the MS are the high inorganic molar N:P ratios, on the order of 20−28, 8,11,45,46 that systematically exceed the Redfield ratio of 16:1. 47 Averaged over the entire MS, the N:P ratio of domestic wastewater inputs is close to the Redfield value (16.1:1).…”

Section: Discussionmentioning

confidence: 99%

Direct Discharges of Domestic Wastewater are a Major Source of Phosphorus and Nitrogen to the Mediterranean Sea

Powley

Dürr

Lima

et al. 2016

Environ. Sci. Technol.

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Direct discharges of treated and untreated wastewater are important sources of nutrients to coastal marine ecosystems and contribute to their eutrophication. Here, we estimate the spatially distributed annual inputs of phosphorus (P) and nitrogen (N) associated with direct domestic wastewater discharges from coastal cities to the Mediterranean Sea (MS). According to our best estimates, in 2003 these inputs amounted to 0.9 x 10 9 mol P yr −1 and 15 x 10 9 mol N yr −1 , that is, values on the same order of magnitude as riverine inputs of P and N to the MS. By 2050, in the absence of any mitigation, population growth plus higher per capita protein intake and increased connectivity to the sewer system are projected to increase P inputs to the MS via direct wastewater discharges by 254, 163, and 32% for South, East, and North Mediterranean countries, respectively. Complete conversion to tertiary wastewater treatment would reduce the 2050 inputs to below their 2003 levels, but at an estimated additional cost of over €2 billion yr −1 . Management of coastal eutrophication may be best achieved by targeting tertiary treatment upgrades to the most affected near-shore areas, while simultaneously implementing legislation limiting P in detergents and increasing wastewater reuse across the entire basin

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P limitation of heterotrophic bacteria and phytoplankton in the northwest Mediterranean

Cited by 343 publications

References 26 publications

Nutrient and light availability regulate the relative contribution of autotrophs and heterotrophs to respiration in freshwater pelagic ecosystems

Nutrient and light availability regulate the relative contribution of autotrophs and heterotrophs to respiration in freshwater pelagic ecosystems

Ecology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

Direct Discharges of Domestic Wastewater are a Major Source of Phosphorus and Nitrogen to the Mediterranean Sea

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