Phytoplankton Photosynthesis in the Atlantic Ocean as Measured from a Submersible Pump and Probe Fluorometer in Situ

Abstract. Mechanisms of tropospheric ozone (O3) formation are generally well understood. However, studies reporting on net ozone production rates (NOPRs) directly derived from in situ observations are challenging and are sparse in number. To analyze the role of nitric oxide (NO) in net ozone production in the upper tropical troposphere above the Atlantic Ocean and western Africa, we present in situ trace gas observations obtained during the CAFE-Africa (Chemistry of the Atmosphere: Field Experiment in Africa) campaign in August and September 2018. The vertical profile of in situ measured NO along the flight tracks reveals lowest NO mixing ratios of less than 20 pptv between 2 and 8 km altitude and highest mixing ratios of 0.15–0.2 ppbv above 12 km altitude. Spatial distribution of tropospheric NO above 12 km altitude shows that the sporadically enhanced local mixing ratios (>0.4 ppbv) occur over western Africa, which we attribute to episodic lightning events. Measured O3 shows little variability in mixing ratios at 60–70 ppbv, with slightly decreasing and increasing tendencies towards the boundary layer and stratosphere, respectively. Concurrent measurements of CO, CH4, OH, HO2 and H2O enable calculations of NOPRs along the flight tracks and reveal net ozone destruction at −0.6 to −0.2 ppbv h−1 below 6 km altitude and balance of production and destruction around 7–8 km altitude. We report vertical average NOPRs of 0.2–0.4 ppbv h−1 above 12 km altitude with NOPRs occasionally larger than 0.5 ppbv h−1 over western Africa coincident with enhanced NO. We compare the observational results to simulated data retrieved from the general circulation model ECHAM/MESSy Atmospheric Chemistry (EMAC). Although the comparison of mean vertical profiles of NO and O3 indicates good agreement, local deviations between measured and modeled NO are substantial. The vertical tendencies in NOPRs calculated from simulated data largely reproduce those from in situ experimental data. However, the simulation results do not agree well with NOPRs over western Africa. Both measurements and simulations indicate that ozone formation in the upper tropical troposphere is NOx limited.

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The first North American record of Carinodens belgicus (Squamata, Mosasauridae) and correlation with the youngest in situ examples from the Maastrichtian type area: palaeoecological implications

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s001677460000007x ◽

2013 ◽

Vol 92 (2-3) ◽

pp. 145-152 ◽

Cited By ~ 3

Author(s):

E.W.A. Mulder ◽

P. Formanoy ◽

W.B. Gallagher ◽

J.W.M. Jagt ◽

A.S. Schulp

Keyword(s):

North America ◽

Atlantic Ocean ◽

North American ◽

Atlantic Coast ◽

First Record ◽

Type Area

AbstractFour recently collected tooth crowns of the rare latest Cretaceous (late Maastrichtian) durophagous mosasaur Carinodens belgicus are discussed; the first record from the Atlantic coast of North America (Maryland), and three additional in situ examples from the Maastrichtian type area in the southeast Netherlands and northeast Belgium. Also presented are an updated overview of the material recorded to date, and a discussion of the palaeobiogeographical and palaeoenvironmental distribution of the genus. Towards the end of the Cretaceous, Carinodens appears to have been successful in exploiting the margins of both the proto-Atlantic Ocean and the Tethyan Realm.

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Benthic community respiration in the N.W. Atlantic Ocean: in situ measurements from 40 to 5200 m

Marine Biology ◽

10.1007/bf00388925 ◽

1978 ◽

Vol 47 (4) ◽

pp. 337-347 ◽

Cited By ~ 128

Author(s):

K. L. Smith

Keyword(s):

Atlantic Ocean ◽

Benthic Community ◽

In Situ Measurements ◽

Community Respiration

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Requirements for an Integrated in situ Atlantic Ocean Observing System From Coordinated Observing System Simulation Experiments

Frontiers in Marine Science ◽

10.3389/fmars.2019.00083 ◽

2019 ◽

Vol 6 ◽

Cited By ~ 12

Author(s):

Florent Gasparin ◽

Stephanie Guinehut ◽

Chongyuan Mao ◽

Isabelle Mirouze ◽

Elisabeth Rémy ◽

...

Keyword(s):

Atlantic Ocean ◽

System Simulation ◽

Simulation Experiments ◽

Ocean Observing

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From In Situ to satellite observations of pelagic Sargassum distribution and aggregation in the Tropical North Atlantic Ocean

PLoS ONE ◽

10.1371/journal.pone.0222584 ◽

2019 ◽

Vol 14 (9) ◽

pp. e0222584 ◽

Cited By ~ 7

Author(s):

Anouck Ody ◽

Thierry Thibaut ◽

Léo Berline ◽

Thomas Changeux ◽

Jean-Michel André ◽

...

Keyword(s):

Atlantic Ocean ◽

North Atlantic ◽

North Atlantic Ocean ◽

Satellite Observations ◽

Tropical North Atlantic

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Heme b distributions through the Atlantic Ocean: in situ identification of iron limited phytoplankton

10.5194/egusphere-egu2020-15577 ◽

2020 ◽

Author(s):

Evangelia Louropoulou ◽

Martha Gledhill ◽

Eric P. Achterberg ◽

Thomas J. Browning ◽

David J. Honey ◽

...

Keyword(s):

Atlantic Ocean ◽

Large Scale ◽

North Atlantic Ocean ◽

Iron Status ◽

Mean Value ◽

Particulate Material ◽

South Atlantic ◽

Phytoplankton Communities ◽

The Impact

Heme b is an iron-containing cofactor in hemoproteins that participates in the fundamental processes of photosynthesis and respiration in phytoplankton. Heme b concentrations typically decline in waters with low iron concentrations but due to lack of field data, the distribution of heme b in particulate material in the ocean is poorly constrained. Within the framework of the Helmholtz Research School for Ocean System Science and Technology (HOSST) and the GEOTRACES programme, the authors compiled datasets and conducted multidisciplinary research (e.g. chemical oceanography, microbiology, biogeochemical modelling) in order to test heme b as an indicator of in situ iron-limited phytoplankton. This study was initiated in the North Atlantic Ocean and expanded to the under-sampled South Atlantic Ocean for comparison of the results considering the different phytoplankton populations. Here, we report particulate heme b distributions across the Atlantic Ocean (59.9&#176;N to 34.6&#176;S). Heme b concentrations in surface waters ranged from 0.10 to 33.7 pmol L-1 (median=1.47 pmol L-1, n=974) and were highest in regions with a high biomass. The ratio of heme b to particulate organic carbon (POC) exhibited a mean value of 0.44 &#956;mol heme b mol-1 POC. We identified the ratio of 0.10 &#181;mol heme b mol-1 POC as the cut-off between heme b replete and heme b deficient phytoplankton. By this definition, the ratio heme b relative to POC was consistently below 0.10 &#956;mol mol-1 in areas characterized by low Fe supply; these were the Subtropical South Atlantic gyre and the seasonally iron limited Irminger Basin. Thus, the ratio heme b relative to POC gave a reliable indication of iron limited phytoplankton communities in situ. Furthermore, the comparison of observed and modelled heme b suggested that heme b could account for between 0.17-9.1% of biogenic iron. This range was comparable to previous culturing observations for species with low heme b content and species growing in low Fe (&#8804;0.50 nmol L-1) or nitrate culturing media. Our large scale observations of heme b relative to organic matter suggest the impact of changes in iron supply on phytoplankton iron status.

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Politolana sanchezi sp. nov. (Crustacea: Isopoda: Cirolanidae), a new benthic bioturbating scavenger from bathyal soft-bottoms of the southern Bay of Biscay (northeastern Atlantic Ocean)

Zootaxa ◽

10.11646/zootaxa.2640.1.2 ◽

2010 ◽

Vol 2640 (1) ◽

pp. 20 ◽

Cited By ~ 4

Author(s):

INMACULADA FRUTOS ◽

JEAN CLAUDE SORBE

Keyword(s):

New Species ◽

Atlantic Ocean ◽

Time Lapse ◽

Fishing Ground ◽

Bay Of Biscay ◽

Continental Slopes ◽

Soft Bottoms ◽

Northeastern Atlantic Ocean ◽

Northeastern Atlantic

A new species of the genus Politolana (Crustacea, Isopoda, Cirolanidae) is described, based on specimens collected from the Le Danois Bank (‘El Cachucho’ fishing ground), southern Bay of Biscay, northeastern Atlantic Ocean. Politolana sanchezi sp. nov. can be distinguished from P. microphthalma (the only Politolana species recorded in boreal European waters) by larger eyes, presence of chromatophores on pereon and pleon, antennae reaching to the middle of the second pereonite, lateral margin of the frontal ridge dividing eyes, superior meral lobe of pereopod 1 reaching midpoint of the propodus, distal end of uropodal endopod subacute and pleotelson apex broadly convex with small medial point. An identification key to the world species of Politolana is presented. The new species has been found living on muddy-fine sandy bottoms of the southern Bay of Biscay and western Galicia, between 480 and 791 m depth. According to the present findings, it belongs to the benthic scavenger guild recognized on continental slopes. Its scavenging and bioturbating behaviour at the sediment-water interface are described from in situ trophic experiments with a fish-baited trap combined with a time-lapse recording camera.

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