scholarly journals Patchy Distributions and Distinct Niche Partitioning of Mycoplankton Populations across a Nearshore to Open Ocean Gradient

2021 ◽  
Author(s):  
Yingbo Duan ◽  
Ningdong Xie ◽  
Zhao Wang ◽  
Zackary I. Johnson ◽  
Dana E. Hunt ◽  
...  
Keyword(s):  
Niche Partitioning ◽  
Coastal Ocean ◽  
Open Ocean ◽  
Marine Environments ◽  
Heterotrophic Microbes ◽  
Terrestrial Inputs

Fungi are an important, but understudied, group of heterotrophic microbes in marine environments. Traditionally, fungi in the coastal ocean were largely assumed to be derived from terrestrial inputs.

scholarly journals Carbon cycling in the North American coastal ocean: A synthesis

2018 ◽  
Author(s):  
Katja Fennel ◽  
Simone Alin ◽  
Leticia Barbero ◽  
Wiley Evans ◽  
Timotheé Bourgeois ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
North American ◽  
Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Fluxes ◽  
Coastal Ocean ◽  
Open Ocean ◽  
The Arctic ◽  
The North ◽  
Anthropogenic Carbon

Abstract. A quantification of carbon fluxes in the coastal ocean and across its boundaries, specifically the air-sea, land-to-coastal-ocean and coastal-to-open-ocean interfaces, is important for assessing the current state and projecting future trends in ocean carbon uptake and coastal ocean acidification, but is currently a missing component of global carbon budgeting. This synthesis reviews recent progress in characterizing these carbon fluxes with focus on the North American coastal ocean. Several observing networks and high-resolution regional models are now available. Recent efforts have focused primarily on quantifying net air-sea exchange of carbon dioxide (CO2). Some studies have estimated other key fluxes, such as the exchange of organic and inorganic carbon between shelves and the open ocean. Available estimates of air-sea CO2 flux, informed by more than a decade of observations, indicate that the North American margins act as a net sink for atmospheric CO2. This net uptake is driven primarily by the high-latitude regions. The estimated magnitude of the net flux is 160 ± 80 Tg C/y for the North American Exclusive Economic Zone, a number that is not well constrained. The increasing concentration of inorganic carbon in coastal and open-ocean waters leads to ocean acidification. As a result conditions favouring dissolution of calcium carbonate occur regularly in subsurface coastal waters in the Arctic, which are naturally prone to low pH, and the North Pacific, where upwelling of deep, carbon-rich waters has intensified and, in combination with the uptake of anthropogenic carbon, leads to low seawater pH and aragonite saturation states during the upwelling season. Expanded monitoring and extension of existing model capabilities are required to provide more reliable coastal carbon budgets, projections of future states of the coastal ocean, and quantification of anthropogenic carbon contributions.

scholarly journals Labile trace metal concentration measurements in marine environments: From coastal to open ocean areas

2019 ◽  
Vol 116 ◽  
pp. 92-101 ◽  
Author(s):  
Yue Gao ◽  
Chunyang Zhou ◽  
Camille Gaulier ◽  
Arne Bratkic ◽  
Josep Galceran ◽  
...  
Keyword(s):  
Trace Metal ◽  
Metal Concentration ◽  
Open Ocean ◽  
Trace Metal Concentration ◽  
Marine Environments ◽  
Concentration Measurements

scholarly journals Geochemical Features of Redox-Sensitive Trace Metals in Sediments under Oxygen-Depleted Marine Environments

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1021
Author(s):  
Moei Yano ◽  
Kazutaka Yasukawa ◽  
Kentaro Nakamura ◽  
Minoru Ikehara ◽  
Yasuhiro Kato
Keyword(s):  
Sedimentary Environment ◽  
Organic Matter Content ◽  
Oxygen Depletion ◽  
Major And Trace Elements ◽  
Matter Content ◽  
Open Ocean ◽  
Chemical Compositions ◽  
Marine Environments ◽  
High Productivity ◽  
Sedimentary Environments

Organic- and sulfide-rich sediments have formed in oxygen-depleted environments throughout Earth’s history. The fact that they are generally enriched in redox-sensitive elements reflects the sedimentary environment at the time of deposition. Although the modern ocean is well oxidized, oxygen depletion occurs in certain areas such as restricted basins and high-productivity zones. We measured bulk chemical compositions (major and trace elements, total organic carbon, and total sulfur) of organic- and sulfide-rich sediments collected from eight areas having oxygen-depleted water to discuss relationships between geochemical features and sedimentary environments. Major elemental compositions generally show mixtures of terrigenous detritus and biogenic carbonate. Some redox-sensitive elements might be controlled by organic matter content, whereas others could be contained in sulfide minerals in sediments. In particular, Mo and U show a characteristic trend; areas with higher Mo and U—at least partially owing to a depositional process called the “particulate shuttle”—generally correspond to regions influenced by the open ocean. In contrast, areas with lower Mo and U are more restricted marine environments. This suggests that the degree of Mo and U enrichment reflects the geography in terms of proximity to the open ocean, or the degree of the supply of these elements from the open ocean.

scholarly journals Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean

2020 ◽  
Vol 117 (36) ◽  
pp. 22281-22292 ◽  
Author(s):  
Mario Lebrato ◽  
Dieter Garbe-Schönberg ◽  
Marius N. Müller ◽  
Sonia Blanco-Ameijeiras ◽  
Richard A. Feely ◽  
...  
Keyword(s):  
International Association ◽  
Open Ocean ◽  
Total Alkalinity ◽  
Polar Regions ◽  
Marine Environments ◽  
Physical Sciences ◽  
Seawater Chemistry ◽  
Sr:Ca Ratios ◽  
Biogeochemical Parameters ◽  
Dynamic Exchange

Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth–ocean–atmosphere dynamic exchange of elements. The ratios’ dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previous data, to test the assumption of limited seawater Mg:Ca and Sr:Ca variability across marine environments globally. High variability was found in open-ocean upwelling and polar regions, shelves/neritic and river-influenced areas, where seawater Mg:Ca and Sr:Ca ratios range from ∼4.40 to 6.40 mmol:mol and ∼6.95 to 9.80 mmol:mol, respectively. Open-ocean seawater Mg:Ca is semiconservative (∼4.90 to 5.30 mol:mol), while Sr:Ca is more variable and nonconservative (∼7.70 to 8.80 mmol:mol); both ratios are nonconservative in coastal seas. Further, the Ca, Mg, and Sr elemental fluxes are connected to large total alkalinity deviations from International Association for the Physical Sciences of the Oceans (IAPSO) standard values. Because there is significant modern seawater Mg:Ca and Sr:Ca ratios variability across marine environments we cannot absolutely assume that fossil archives using taxa-specific proxies reflect true global seawater chemistry but rather taxa- and process-specific ecosystem variations, reflecting regional conditions. This variability could reconcile secular seawater Mg:Ca and Sr:Ca ratio reconstructions using different taxa and techniques by assuming an error of 1 to 1.50 mol:mol, and 1 to 1.90 mmol:mol, respectively. The modern ratios’ variability is similar to the reconstructed rise over 20 Ma (Neogene Period), nurturing the question of seminonconservative behavior of Ca, Mg, and Sr over modern Earth geological history with an overlooked environmental effect.

Environmental impacts of brass mesh nets on open ocean aquaculture pens in tropical marine environments

Aquaculture ◽  
2020 ◽  
Vol 524 ◽  
pp. 735266
Author(s):  
Tyler Sclodnick ◽  
Steve Sutton ◽  
Thomas Selby ◽  
Robert Dwyer ◽  
Langley Gace
Keyword(s):  
Environmental Impacts ◽  
Open Ocean ◽  
Marine Environments ◽  
Open Ocean Aquaculture

Coastal ocean dynamics reduce the export of microplastics to the open ocean

2020 ◽  
Vol 713 ◽  
pp. 136634 ◽  
Author(s):  
Zhiwei Zhang ◽  
Hui Wu ◽  
Guyu Peng ◽  
Pei Xu ◽  
Daoji Li
Keyword(s):  
Coastal Ocean ◽  
Open Ocean ◽  
Ocean Dynamics

scholarly journals Aliased Tidal Variability in Mesoscale Sea Level Anomaly Maps

2018 ◽  
Vol 35 (12) ◽  
pp. 2421-2435 ◽  
Author(s):  
Edward D. Zaron ◽  
Richard D. Ray
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Objective Assessment ◽  
Coastal Ocean ◽  
Open Ocean ◽  
Objective Analysis ◽  
Small Scale ◽  
Phase Variable ◽  
Sea Level Anomaly ◽  
Tidal Variability

AbstractSea level anomaly (SLA) maps are routinely produced by objective analysis of data from the constellation of satellite altimeter missions in operation since 1992. Beginning in 2014, changes in the Data Unification and Altimeter Combination System (DUACS) used to create the SLA maps resulted in improved spatial resolution of mesoscale variability, but it also increased the levels of aliased tidal variability compared to the methodology employed prior to 2014. The present work investigates the magnitude and spatial distribution of these tidal signals, which are typically smaller than 1 cm in the open ocean but can reach tens of centimeters in the coastal ocean. In the open ocean, the signals are caused by a combination of phase-locked and phase-variable baroclinic tides. In the coastal ocean, the signals are a combination of aliased high-frequency nontidal variability and aliased variability caused by erroneous tidal corrections applied to the along-track altimetry prior to objective analysis. Several low-pass and bandpass filters are implemented to reduce the tidal signals in the mapped SLA, and independent tide gauge data are used to provide an objective assessment of the performance of the filters. The filter that attenuates both the small-scale (less than 200 km) and the high-frequency (period shorter than 108 days) components of SLA removes aliased baroclinic tidal variability and improves the accuracy of tidal analysis in the open ocean while also performing acceptably in the coastal ocean.

Mechanisms driving seawater pCO2 spatiotemporal variability in the Canary-Iberian Upwelling System

2020 ◽  
Author(s):  
Daniel Broullón ◽  
Rita Nolasco ◽  
Rosa Reboreda ◽  
Jesus Dubert ◽  
Marion Gehlen ◽  
...  
Keyword(s):  
Time Series ◽  
Inorganic Carbon ◽  
Coastal Ocean ◽  
Open Ocean ◽  
Total Alkalinity ◽  
Spatiotemporal Variability ◽  
Positive Anomaly ◽  
Upwelling System ◽  
Minor Influence ◽  
A Minor

<p>Upwelling systems are very productive regions of the ocean that strongly contribute to the local economies holding very different fisheries. These dynamic systems are characterized by a high degree of spatial and temporal variability of biogeochemical properties, including carbon, which is generally poorly represented in coarse-resolution global models. The importance of the marine carbon system characterizing these systems has been demonstrated in different regions from multiple perspectives. For the first time, we evaluate the drivers of the spatiotemporal variability of the seawater partial pressure of CO<sub>2</sub> (pCO<sub>2</sub>) in the Canary-Iberian Upwelling System (25.5-45ºN, 5.5-20.5ºW) to better understand the inorganic carbon cycle in this highly-productive upwelling region. To do so, we first coupled a regional high-resolution ocean circulation model CROCO with the ocean biogeochemical model PISCES and run a climatological simulation. A first-order Taylor expansion was applied over this simulation to compute the contribution of four variables to the pCO<sub>2</sub> spatiotemporal variability: salinity-normalized dissolved inorganic carbon (sC<sub>T</sub>), salinity-normalized total alkalinity (sA<sub>T</sub>), temperature (T) and freshwater fluxes (FW). Modeled pCO<sub>2</sub> is in agreement with that of recent data-based monthly climatologies (open ocean RMSE: 5.2-10.8 µatm; coastal ocean RMSE: 7.9-18.7 µatm), measured data from the Surface Ocean CO₂ Atlas (SOCAT) (RMSE: 6.6-13.9 µatm) and computed pCO<sub>2</sub> from measured A<sub>T</sub> and pH at the European Station for Time series in the Ocean Canary islands (ESTOC) (RMSE: 5.1 µatm). The spatial distribution of the pCO<sub>2</sub> anomalies relative to the domain mean shows two different areas with opposite anomalies: positive anomalies around the coast in the entire domain and in open ocean south of 33ºN and negative anomalies in open ocean north of 33ºN. This pattern is mainly driven by the contribution of the T component and a minor influence of sA<sub>T</sub> and FW, with the sC<sub>T</sub> component largely counteracting the effects of the other drivers but contributing to the positive anomaly along the Iberian coast. The seasonal variability is controlled by T and sC<sub>T</sub>, with a minor influence of sA<sub>T</sub> and a negligible importance of FW. The seasonal cycle shows a direct covariation between the T contribution and the δpCO2 (monthly mean minus annual mean of pCO<sub>2</sub>) and an inverse covariation between the sC<sub>T</sub> contribution and the δpCO<sub>2</sub> that counteracts the effect of T in the δpCO<sub>2</sub> amplitude. A decrease in the δpCO<sub>2</sub> amplitude was found from open ocean (depths > 200m) to coastal ocean (depths < 200m) determined mainly by a decrease in the influence of the T driver and, less significant, also by a reduction of the sC<sub>T</sub> contribution. The general agreement between modeled and observed contributions to pCO<sub>2</sub> variability at the ESTOC time-series station, in terms of both phase and amplitude, lends credibility to our deconvolution and model, which has been applied across the Canary-Iberian Upwelling System, to assess the processes behind the spatiotemporal variability of pCO<sub>2</sub>.</p>

scholarly journals Riverine influence on the tropical Atlantic Ocean biogeochemistry

2013 ◽  
Vol 10 (10) ◽  
pp. 6357-6373 ◽  
Author(s):  
L. C. da Cunha ◽  
E. T. Buitenhuis
Keyword(s):  
Atlantic Ocean ◽  
Coastal Ocean ◽  
Open Ocean ◽  
N Fixation ◽  
South American ◽  
Tropical Atlantic ◽  
Co2 Fluxes ◽  
Tropical Atlantic Ocean ◽  
Ocean Biogeochemistry

Abstract. We assess the role of riverine inputs of N, Si, Fe, organic and inorganic C in the tropical Atlantic Ocean using a global ocean biogeochemistry model. We use a standard model scenario and three sensitivity tests to investigate the role of total river nutrient and carbon inputs, as well as the western (South American) and eastern (African) river inputs on the tropical Atlantic Ocean biogeochemistry, between 20° S–20° N and 70° W–20° E. Increased nutrient availability from river inputs in this area (compared to a sensitivity scenario without river nutrient inputs, NO_RIVER) leads to an increase in primary production (PP) and export production (EP), mainly in the coastal ocean area (modeled ocean area with bathymetry <200 m). Model results suggest an enhanced N-fixation by diazotrophs on the tropical Atlantic mainly in open ocean areas. The increased rate of N-fixation in the TODAY scenario is proportional to the increase in PP and EP relative to the NO_RIVER scenario, and may support up to 14% of the coastal ocean export production. Inputs from South American rivers have an impact in coastal PP and EP two times higher than those from African rivers. On the other hand, results suggest that the contribution of African and South American rivers to the total increase in open ocean PP and EP is similar. Considering the amount of delivered nutrients (2–3 times less nutrients and carbon inputs by African rivers) one concludes that African riverine inputs may have a larger impact on the whole tropical Atlantic Ocean biogeochemistry. This is probably due to a combination of nutrient trapping in upwelling areas off the large rivers' outflows and shallow mixed layers in the eastern tropical Atlantic, concomitantly to the differences in delivered nutrient ratios leading to alleviation in limitation conditions, mainly for diatoms. When river inputs are added to the model, we estimate a modest decrease in open ocean sea-air CO2 fluxes (−5.2 Tg C a−1) and an increase in coastal ocean CO2 fluxes, mainly provoked by the remineralization of riverine organic matter delivered by the South American rivers.

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