Zinc marine biogeochemistry in seawater: a review

2012 ◽  
Vol 63 (7) ◽  
pp. 644 ◽  
Author(s):  
Marie Sinoir ◽  
Edward C. V. Butler ◽  
Andrew R. Bowie ◽  
Mathieu Mongin ◽  
Pavel N. Nesterenko ◽  
...  
Keyword(s):  
Surface Waters ◽  
Phytoplankton Community ◽  
Conceptual Models ◽  
Biogeochemical Cycles ◽  
Phytoplankton Growth ◽  
Laboratory Studies ◽  
Marine Systems ◽  
Subtle Effect ◽  
Marine Biogeochemistry ◽  
Marine Surface

The interest in trace element biogeochemistry has arisen from the well demonstrated iron hypothesis that revealed the central role that iron exerts on oceanic primary and associated biogeochemical cycles. The essentiality of zinc for key biological enzymes, coupled with a nutrient-like vertical distribution with low dissolved concentrations in many marine surface waters, provided motivation to study zinc in marine systems. Laboratory studies have confirmed the importance of zinc to sustain phytoplankton growth and its influence on the composition of the phytoplankton community. However, mixed results were obtained in the field, which suggest a more subtle effect of zinc on oceanic phytoplankton growth than iron. As a consequence, consensus on its biological role, mechanisms at play or regional versus global relevance is currently lacking and highlights the need for new conceptual models of zinc in marine systems. The recent GEOTRACES program is generating new data approaches to discuss and understand further zinc behaviour in the ocean.

scholarly journals Rates of primary production in groundwater rival those in oligotrophic marine systems

2021 ◽  
Author(s):  
Will A Overholt ◽  
Susan Trumbore ◽  
Xiaomei Xu ◽  
Till L V Bornemann ◽  
Alexander J Probst ◽  
...  
Keyword(s):  
Primary Production ◽  
Surface Waters ◽  
Carbon Fixation ◽  
Euphotic Zone ◽  
Rate Data ◽  
Carbonate Aquifer ◽  
Marine Systems ◽  
Marine Surface ◽  
Terrestrial Subsurface

The terrestrial subsurface contains nearly all of Earth's freshwater reserves and harbors upwards of 60% of our planet's total prokaryotic biomass. While genetic surveys suggest these organisms rely on in situ carbon fixation, rather than the translocation of photosynthetically derived organic carbon, corroborating measurements of carbon fixation in the subsurface are absent. Using a novel ultra-low level 14C-labeling technique, we show that in situ carbon fixation rates in a carbonate aquifer reached 10% of the median rates measured in oligotrophic marine surface waters, and were up to six-fold greater than those observed in lower euphotic zone waters where deep chlorophyll levels peak. Empirical carbon fixation rates were substantiated by both nitrification and anammox rate data. Metagenomic analyses revealed a remarkable abundance of putative chemolithoautotrophic members of an uncharacterized order of Nitrospiria - the first representatives of this class expected to fix carbon via the Wood-Ljungdahl pathway. Based on these fixation rates, we extrapolate global primary production in carbonate groundwaters to be 0.11 Pg of carbon per year.

The Redfield Ratio and Phytoplankton Growth Rate

1985 ◽  
Vol 65 (2) ◽  
pp. 487-504 ◽  
Author(s):  
P. Tett ◽  
M. R. Droop ◽  
S. I. Heaney
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Surface Waters ◽  
Growth Rates ◽  
Phytoplankton Growth ◽  
Maximal Growth ◽  
Redfield Ratio ◽  
Phytoplankton Growth Rate ◽  
Marine Surface ◽  
Natural Phytoplankton

Goldman, McCarthy & Peavey (1979b) argued that growth rates of phyto-plankton in apparently oligotrophic ocean waters may near maximal. Their hypothesis was succinctly restated by Goldman (1980): ‘…the chemical composition of phytoplankton is extremely variable under exacting laboratory conditions of nutrient limitation and approaches the ‘Redfield’ proportions (C:N:P of 106:16:1) when neither nitrogen nor phosphorus is limiting so that near maximal growth rates are attained. In marine surface waters the chemical composition of particular matter often is in the Redfield proportions, thus implying that natural phytoplankton growth rates may be close to maximal.’ We argue on theoretical, experimental and observational grounds that this implication may not necessarily be correct.

scholarly journals Insights into biotic and abiotic modulation of ocean mesopelagic communities

2021 ◽  
Author(s):  
Janaina Rigonato ◽  
Marko Budinich ◽  
Alejandro A. Murillo ◽  
Manoela C. Brandão ◽  
Juan J. Pierella Karlusich ◽  
...  
Keyword(s):  
Surface Waters ◽  
Network Inference ◽  
Biogeochemical Cycles ◽  
Environmental Drivers ◽  
Abiotic Factor ◽  
Marine Habitat ◽  
Mesopelagic Zone ◽  
Minimum Zone ◽  
Globally Distributed ◽  
Oxygen Minimum

AbstractMarine plankton mitigate anthropogenic greenhouse gases, modulate biogeochemical cycles, and provide fishery resources. Plankton is distributed across a stratified ecosystem of sunlit surface waters and a vast, though understudied, mesopelagic ‘dark ocean’. In this study, we mapped viruses, prokaryotes, and pico-eukaryotes across 32 globally-distributed cross-depth samples collected during the Tara Oceans Expedition, and assessed their ecologies. Based on depth and O2 measurements, we divided the marine habitat into epipelagic, oxic mesopelagic, and oxygen minimum zone (OMZ) eco-regions. We identified specific communities associated with each marine habitat, and pinpoint environmental drivers of dark ocean communities. Our results indicate that water masses primarily control mesopelagic community composition. Through co-occurrence network inference and analysis, we identified signature communities strongly associated with OMZ eco-regions. Mesopelagic communities appear to be constrained by a combination of factors compared to epipelagic communities. Thus, variations in a given abiotic factor may cause different responses in sunlit and dark ocean communities. This study expands our knowledge about the ecology of planktonic organisms inhabiting the mesopelagic zone.

scholarly journals Seasonal and spatial comparisons of phytoplankton growth and mortality rates due to microzooplankton grazing in the northern South China Sea

2012 ◽  
Vol 9 (11) ◽  
pp. 16005-16032
Author(s):  
B. Chen ◽  
L. Zheng ◽  
B. Huang ◽  
S. Song ◽  
H. Liu
Keyword(s):  
South China Sea ◽  
Mixed Layer ◽  
South China ◽  
Surface Waters ◽  
Northern South China Sea ◽  
Phytoplankton Growth ◽  
China Sea ◽  
Grazing Effect ◽  
Basin Surface ◽  
Microzooplankton Grazing

Abstract. We conducted a comprehensive investigation on the microzooplankton herbivory effect on phytoplankton in the northern South China Sea (SCS) using the seawater dilution technique at surface and deep chlorophyll maximum (DCM) layers in two cruises (July–August of 2009 and January of 2010). We compared vertical (surface vs. DCM), spatial (onshore vs. offshore), and seasonal (summer vs. winter) differences of phytoplankton growth (μ0) and microzooplankton grazing rates (m). During summer, both μ0 and m were significantly higher at the surface than at the layer of DCM, which was below the mixed layer. During winter, surface μ0 was significantly higher than at DCM, while m was not significantly different between the two layers, both of which were contained within the mixed layer. Surface μ0 was, on average, significantly higher in summer than in winter; while average surface m was not different between the two seasons. There were no significant cross-shelf trends of μ0 in summer or winter surface waters. In surface waters, μ0 was not correlated with ambient nitrate concentrations and the effect of nutrient enrichment on phytoplankton growth was not pronounced. There was a decreasing trend of m from shelf to basin surface waters in summer, but not in winter. Microzooplankton grazing effect on phytoplankton (m/μ0) did not increase with distance offshore, suggesting that the importance of microzooplankton as grazers of phytoplankton may not decrease in onshore waters. On average, microzooplankton grazed 73% and 65% of the daily primary production in summer and winter, respectively.

Estimation of Biologically Damaging UV Levels in Marine Surface Waters with DNA and Viral Dosimeters¶

2007 ◽  
Vol 76 (3) ◽  
pp. 268-273 ◽  
Author(s):  
Steven W. Wilhelm ◽  
Wade H. Jeffrey ◽  
Curtis A. Suttle ◽  
David L. Mitchell
Keyword(s):  
Surface Waters ◽  
Marine Surface

Iron plays a role in nitrate drawdown by phytoplankton in Lake Erie surface waters as observed in lake-wide assessments

2012 ◽  
Vol 69 (2) ◽  
pp. 369-381 ◽  
Author(s):  
Sonya M. Havens ◽  
Christel S. Hassler ◽  
Rebecca L. North ◽  
Stephanie J. Guildford ◽  
Greg Silsbe ◽  
...  
Keyword(s):  
Surface Waters ◽  
Thermal Stratification ◽  
Lake Erie ◽  
Phytoplankton Community ◽  
Sampling Depth ◽  
Phytoplankton Pigment ◽  
Chl A ◽  
Dissolved Iron ◽  
Continuous Surface

Phytoplankton interactions with iron (Fe) were examined in surface waters of Lake Erie during summer thermal stratification. Lake-wide sampling in June and September 2005 was conducted using a continuous surface water sampler (1 m sampling depth) and in July at 18 hydrographic stations (5 m sampling depth). In situ measurements of photosynthetic efficiency (maximum quantum yield of photosystem II) and phytoplankton community composition were measured using fast repetition rate fluorometry and a phytoplankton pigment-specific fluorometer, respectively, during June and September. High ratios (73%–85%) of intracellular Fe to particulate Fe coincident with increases in chlorophyll a (Chl a) concentrations in the western and central basins in June and July imply that the majority of Fe in these regions was associated with intracellular pools. Correlations between intracellular Fe and Chl a were frequently observed when Heterokontophyta and Pyrrophyta dominated the phytoplankton community. Assimilation of Fe by the phytoplankton strongly influenced its partitioning between the dissolved and particulate phase. Dissolved iron (<0.45 µm) concentrations were proportional to Chl a concentrations and both dissolved iron and Chl a were inversely proportional to nitrate concentrations in July and September, suggesting that dissolved iron influenced both nitrate drawdown and Chl a concentrations in Lake Erie surface waters in summer.

scholarly journals What limits photosynthetic energy conversion efficiency in nature? Lessons from the oceans

2017 ◽  
Vol 372 (1730) ◽  
pp. 20160376 ◽  
Author(s):  
Paul G. Falkowski ◽  
Hanzhi Lin ◽  
Maxim Y. Gorbunov
Keyword(s):  
Quantum Yield ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Surface Waters ◽  
Phytoplankton Community ◽  
Inorganic Nitrogen ◽  
Photosynthetic Apparatus ◽  
Energy Conversion Efficiency ◽  
Thermal Dissipation ◽  
Essential Components

Constraining photosynthetic energy conversion efficiency in nature is challenging. In principle, two yield measurements must be made simultaneously: photochemistry, fluorescence and/or thermal dissipation. We constructed two different, extremely sensitive and precise active fluorometers: one measures the quantum yield of photochemistry from changes in variable fluorescence, the other measures fluorescence lifetimes in the picosecond time domain. By deploying the pair of instruments on eight transoceanic cruises over six years, we obtained over 200 000 measurements of fluorescence yields and lifetimes from surface waters in five ocean basins. Our results revealed that the average quantum yield of photochemistry was approximately 0.35 while the average quantum yield of fluorescence was approximately 0.07. Thus, closure on the energy budget suggests that, on average, approximately 58% of the photons absorbed by phytoplankton in the world oceans are dissipated as heat. This extraordinary inefficiency is associated with the paucity of nutrients in the upper ocean, especially dissolved inorganic nitrogen and iron. Our results strongly suggest that, in nature, most of the time, most of the phytoplankton community operates at approximately half of its maximal photosynthetic energy conversion efficiency because nutrients limit the synthesis or function of essential components in the photosynthetic apparatus. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.

Phytoplankton growth under temperature stress: Laboratory studies using two diatoms from a tropical coastal power station site

2005 ◽  
Vol 30 (4) ◽  
pp. 299-305 ◽  
Author(s):  
M. Rajadurai ◽  
E.H. Poornima ◽  
S.V. Narasimhan ◽  
V.N.R. Rao ◽  
V.P. Venugopalan
Keyword(s):  
Temperature Stress ◽  
Phytoplankton Growth ◽  
Laboratory Studies ◽  
Power Station ◽  
Station Site
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