scholarly journals Eddy- and wind-sustained moderate primary productivity in the temperate East Sea (Sea of Japan)

2013 ◽  
Vol 10 (6) ◽  
pp. 10429-10458 ◽  
Author(s):  
G.-H. Hong ◽  
D.-K. Lee ◽  
D.-B. Yang ◽  
Y. I. Kim ◽  
J.-H. Park ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Water ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Phytoplankton Bloom ◽  
Mesoscale Eddy ◽  
Japan Sea ◽  
East Sea ◽  
Subsurface Water ◽  
Water Current

Abstract. As part of the Dokdo East Sea Time Series Studies (DETS) in the East/Japan Sea, a DETS buoy system was moored on the 130 m deep continental shelf off the Dok Islets in the central part of the East Sea. Chlorophyll a concentrations in the surface water observed by the DETS buoy system exhibited low-frequency bimodal variations in the annual chlorophyll a concentration due to a spring phytoplankton bloom and a smaller fall bloom. In addition, between late spring and early fall when the water column is stratified, frequent low-concentration maxima occurred, which appear to have been triggered by the injection of nutrient-rich subsurface water to the sunlit surface water. The primary productivity in the nutrient-depleted surface ocean was found to be enhanced by subsurface water upwelling where the wind and water move in the same direction as the mesoscale eddy. New observations in the East/Japan Sea based on time-series measurements of chlorophyll a, wind, and other oceanographic variables at fixed sites in the center of the sea and using satellite measurements reveal that the vertical movement of water caused by wind-eddy interactions depends on the relative angle between the wind and the water current. The wind-eddy interaction appears to contribute to the unusually high primary productivity in the region where it was often sustained by the long-lived warm and cold eddies.

scholarly journals Estimation of the Particulate Organic Carbon to Chlorophyll-a Ratio Using MODIS-Aqua in the East/Japan Sea, South Korea

2020 ◽  
Vol 12 (5) ◽  
pp. 840 ◽  
Author(s):  
Dabin Lee ◽  
SeungHyun Son ◽  
HuiTae Joo ◽  
Kwanwoo Kim ◽  
Myung Joon Kim ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Seasonal Variability ◽  
Japan Sea ◽  
Global Ocean ◽  
Phytoplankton Communities

In recent years, the change of marine environment due to climate change and declining primary productivity have been big concerns in the East/Japan Sea, Korea. However, the main causes for the recent changes are still not revealed clearly. The particulate organic carbon (POC) to chlorophyll-a (chl-a) ratio (POC:chl-a) could be a useful indicator for ecological and physiological conditions of phytoplankton communities and thus help us to understand the recent reduction of primary productivity in the East/Japan Sea. To derive the POC in the East/Japan Sea from a satellite dataset, the new regional POC algorithm was empirically derived with in-situ measured POC concentrations. A strong positive linear relationship (R2 = 0.6579) was observed between the estimated and in-situ measured POC concentrations. Our new POC algorithm proved a better performance in the East/Japan Sea compared to the previous one for the global ocean. Based on the new algorithm, long-term POC:chl-a ratios were obtained in the entire East/Japan Sea from 2003 to 2018. The POC:chl-a showed a strong seasonal variability in the East/Japan Sea. The spring and fall blooms of phytoplankton mainly driven by the growth of large diatoms seem to be a major factor for the seasonal variability in the POC:chl-a. Our new regional POC algorithm modified for the East/Japan Sea could potentially contribute to long-term monitoring for the climate-associated ecosystem changes in the East/Japan Sea. Although the new regional POC algorithm shows a good correspondence with in-situ observed POC concentrations, the algorithm should be further improved with continuous field surveys.

scholarly journals Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

Elem Sci Anth ◽  
2020 ◽  
Vol 8 ◽  
Author(s):  
Elizabeth M. Jones ◽  
Angelika H. H. Renner ◽  
Melissa Chierici ◽  
Ingrid Wiedmann ◽  
Helene Hodal Lødemel ◽  
...  
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Phytoplankton Bloom ◽  
Biogeochemical Cycling ◽  
Atmospheric Co2 ◽  
Subsurface Water ◽  
Series Data ◽  
Co2 Uptake ◽  
Arctic Fjord ◽  
The Impact

Environmental change can have a significant impact on biogeochemical cycles at high latitudes and be particularly important in ecologically valuable fjord ecosystems. Seasonality in biogeochemical cycling in a sub-Arctic fjord of northern Norway (Kaldfjorden) was investigated from October 2016 to September 2018. Monthly changes in total inorganic carbon (CT), alkalinity (AT), major nutrients and calcium carbonate saturation (Ω) were driven by freshwater discharge, biological production and mixing with subsurface carbon-rich coastal water. Stable oxygen isotope ratios indicated that meteoric water (snow melt, river runoff, precipitation) had stratified and freshened surface waters, contributing to 81% of the monthly CT deficit in the surface layer. The timing and magnitude of freshwater inputs played an important role in Ω variability, reducing AT and CT by dilution. This dilution effect was strongly counteracted by the opposing effect of primary production that dominated surface water Ω seasonality. The spring phytoplankton bloom rapidly depleted nitrate and CT to drive highest Ω (~2.3) in surface waters. Calcification reduced AT and CT, which accounted for 21% of the monthly decrease in Ω during a coccolithophore bloom. Freshwater runoff contributed CT, AT and silicates of terrestrial origin to the fjord. Lowest surface water Ω (~1.6) resulted from organic matter remineralisation and mixing into subsurface water during winter and spring. Surface waters were undersaturated with respect to atmospheric CO2, resulting in modest uptake of –0.32 ± 0.03 mol C m–2 yr–1. Net community production estimated from carbon drawdown was 14 ± 2 g C m–2 yr–1 during the productive season. Kaldfjorden currently functions as an atmospheric CO2 sink of 3.9 ± 0.3 g C m–2 yr–1. Time-series data are vital to better understand the processes and natural variability affecting biogeochemical cycling in dynamic coastal regions and thus better predict the impact of future changes on important fjord ecosystems.

scholarly journals Impact of an anticyclonic eddy on the summer nutrient and chlorophyll a distributions in the Ulleung Basin, East Sea (Japan Sea)

2011 ◽  
Vol 69 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Dongseon Kim ◽  
Eun Jin Yang ◽  
Kyung Hee Kim ◽  
Chang-Woong Shin ◽  
Jisoo Park ◽  
...  
Keyword(s):  
Water Column ◽  
Chlorophyll A ◽  
Surface Waters ◽  
Japan Sea ◽  
Anticyclonic Eddy ◽  
East Sea ◽  
Ulleung Basin ◽  
Surface Mixed Layer ◽  
High Concentration ◽  
Chl A

Abstract Kim, D., Yang, E. J., Kim, K. H., Shin, C-W., Park, J., Yoo, S., and Hyun, J-H. 2012. Impact of an anticyclonic eddy on the summer nutrient and chlorophyll a distributions in the Ulleung Basin, East Sea (Japan Sea). – ICES Journal of Marine Science, 69: 23–29. The impact of the anticyclonic Ulleung Warm Eddy (UWE) on the vertical distributions of nutrient and chlorophyll a (Chl a) concentrations in the Ulleung Basin (UB) was investigated during the contrasting summers of 2005 and 2007. The physical structure of the water column was characterized by an intrathermocline eddy (ITE) in 2005, whereas the UWE remained distant from the sampling transect in 2007. Water column structures appeared to be highly stratified, and nutrients in the surface waters were totally depleted at all stations. In 2005, an exceptionally high concentration of Chl a (5.5 mg m−3) was measured below the surface mixed layer in the eddy core (station D3), and values of ∼2.5 mg m–3 were observed at the eddy edge (stations D2 and D4). Formation of an ITE efficiently mixed surface and deep-ocean waters, the latter supplying sufficient nutrients to generate an extremely high concentration of Chl a at the base of the subsurface layer. Overall, the results indicated that the anticyclonic UWE plays a key ecological role in supporting substantial phytoplankton biomass in the nutrient-depleted surface waters in summer and maintaining high benthic mineralization in the deep-sea sediments of the UB.

scholarly journals Remote sensing of coccolithophore blooms in selected oceanic regions using the PhytoDOAS method applied to hyper-spectral satellite data

2011 ◽  
Vol 8 (6) ◽  
pp. 11725-11765
Author(s):  
A. Sadeghi ◽  
T. Dinter ◽  
M. Vountas ◽  
B. Taylor ◽  
M. Altenburg-Soppa ◽  
...  
Keyword(s):  
Time Series ◽  
Chlorophyll A ◽  
Satellite Data ◽  
Phytoplankton Bloom ◽  
Mixed Layer Depth ◽  
Surface Wind ◽  
Temporal Variations ◽  
Data Set ◽  
Mean Values ◽  
Hyper Spectral

Abstract. In this study temporal variations of coccolithophore blooms are investigated using satellite data. Eight years, from 2003 to 2010, of data of SCIAMACHY, a hyper-spectral satellite sensor on-board ENVISAT, were processed by the PhytoDOAS method to monitor the biomass of coccolithophores in three selected regions. These regions are characterized by frequent occurrence of large coccolithophore blooms. The retrieval results, shown as monthly mean time-series, were compared to related satellite products, including the total surface phytoplankton, i.e., total chlorophyll-a (from GlobColour merged data) and the particulate inorganic carbon (from MODIS-Aqua). The inter-annual variations of the phytoplankton bloom cycles and their maximum monthly mean values have been compared in the three selected regions to the variations of the geophysical parameters: sea-surface temperature (SST), mixed-layer depth (MLD) and surface wind speed, which are known to affect phytoplankton dynamics. For each region the anomalies and linear trends of the monitored parameters over the period of this study have been computed. The patterns of total phytoplankton biomass and specific dynamics of coccolithophores chlorophyll-a in the selected regions are discussed in relation to other studies. The PhytoDOAS results are consistent with the two other ocean color products and support the reported dependencies of coccolithophore biomass' dynamics to the compared geophysical variables. This suggests, that PhytoDOAS is a valid method for retrieving coccolithophore biomass and for monitoring its bloom developments in the global oceans. Future applications of time-series studies using the PhytoDOAS data set are proposed, also using the new upcoming generations of hyper-spectral satellite sensors with improved spatial resolution.

scholarly journals Applications of DINEOF to Satellite-Derived Chlorophyll-a from a Productive Coastal Region

2018 ◽  
Vol 10 (9) ◽  
pp. 1449 ◽  
Author(s):  
Andrea Hilborn ◽  
Maycira Costa
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Chlorophyll A ◽  
Spatial Data ◽  
Phytoplankton Bloom ◽  
Input Image ◽  
Empirical Orthogonal Functions ◽  
Series Length ◽  
Explained Variance

A major limitation for remote sensing analyses of oceanographic variables is loss of spatial data. The Data INterpolating Empirical Orthogonal Functions (DINEOF) method has demonstrated effectiveness for filling spatial gaps in remote sensing datasets, making them more easily implemented in further applications. However, the spatial and temporal coverage of the input image dataset can heavily impact the outcomes of using this method and, thus, further metrics derived from these datasets, such as phytoplankton bloom phenology. In this study, we used a three-year time series of MODIS-Aqua chlorophyll-a to evaluate the DINEOF reconstruction output accuracy corresponding to variation in the form of the input data used (i.e., daily or week composite scenes) and time series length (annual or three consecutive years) for a dynamic region, the Salish Sea, Canada. The accuracy of the output data was assessed considering the original chla pixels. Daily input time series produced higher accuracy reconstructing chla (95.08–97.08% explained variance, RMSExval 1.49–1.65 mg m−3) than did all week composite counterparts (68.99–76.88% explained variance, RMSExval 1.87–2.07 mg m−3), with longer time series producing better relationships to original chla pixel concentrations. Daily images were assessed relative to extracted in situ chla measurements, with original satellite chla achieving a better relationship to in situ matchups than DINEOF gap-filled chla, and with annual DINEOF-processed data performing better than the multiyear. These results contribute to the ongoing body of work encouraging production of ocean color datasets with consistent processing for global purposes such as climate change studies.

scholarly journals Remote sensing of coccolithophore blooms in selected oceanic regions using the PhytoDOAS method applied to hyper-spectral satellite data

2012 ◽  
Vol 9 (6) ◽  
pp. 2127-2143 ◽  
Author(s):  
A. Sadeghi ◽  
T. Dinter ◽  
M. Vountas ◽  
B. Taylor ◽  
M. Altenburg-Soppa ◽  
...  
Keyword(s):  
Time Series ◽  
Chlorophyll A ◽  
Satellite Data ◽  
Phytoplankton Bloom ◽  
Mixed Layer Depth ◽  
Surface Wind ◽  
Temporal Variations ◽  
Data Set ◽  
Mean Values ◽  
Hyper Spectral

Abstract. In this study temporal variations of coccolithophore blooms are investigated using satellite data. Eight years (from 2003 to 2010) of data of SCIAMACHY, a hyper-spectral satellite sensor on-board ENVISAT, were processed by the PhytoDOAS method to monitor the biomass of coccolithophores in three selected regions. These regions are characterized by frequent occurrence of large coccolithophore blooms. The retrieval results, shown as monthly mean time series, were compared to related satellite products, including the total surface phytoplankton, i.e. total chlorophyll a (from GlobColour merged data) and the particulate inorganic carbon (from MODIS-Aqua). The inter-annual variations of the phytoplankton bloom cycles and their maximum monthly mean values have been compared in the three selected regions to the variations of the geophysical parameters: sea-surface temperature (SST), mixed-layer depth (MLD) and surface wind-speed, which are known to affect phytoplankton dynamics. For each region, the anomalies and linear trends of the monitored parameters over the period of this study have been computed. The patterns of total phytoplankton biomass and specific dynamics of coccolithophore chlorophyll a in the selected regions are discussed in relation to other studies. The PhytoDOAS results are consistent with the two other ocean color products and support the reported dependencies of coccolithophore biomass dynamics on the compared geophysical variables. This suggests that PhytoDOAS is a valid method for retrieving coccolithophore biomass and for monitoring its bloom developments in the global oceans. Future applications of time series studies using the PhytoDOAS data set are proposed, also using the new upcoming generations of hyper-spectral satellite sensors with improved spatial resolution.

scholarly journals Phytoplankton primary production in southern Iraqi marshes after restoration

2011 ◽  
Vol 8 (1) ◽  
pp. 519-530 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Surface Water ◽  
Oxygen Saturation ◽  
Water Sample ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Surface Water Sample ◽  
Phytoplankton Primary Production ◽  
Dark Bottle ◽  
Different Depths ◽  
Saturation Rate

Primary productivity and chlorophyll-a were used in this study to monitor the restoration process of southern Iraqi marshes (Al-Hewaizeh, central marshes, and Al-Hammar). The phytoplankton primary productivity was based on oxygen light/dark bottle method. Two different depths samples were taken monthly from six studied marshes stations (two stations for each marsh) during November 2005 to October 2006, while chlorophyll-a samples taken from surface water. The phytoplankton primary productivity values ranged 9.38 – 249.79 mg C/m3.hr for all marshes, its values for surface water sample ranged 11.71 – 256.24 mg C/m3.hr, while for 1m depth ranged 9.38 – 142.5 mg C/m3.hr. Chlorophyll-a values ranged between (1.1 – 21.26) µg/l indicating high values of productivity in the studied marshes comparing with other aquatic Iraqi ecosystems. Also, dissolved oxygen and oxygen saturation rate were measured in this study.

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