Spatial and seasonal variability of chlorophyll a in different-sized lakes across eastern China

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.

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Seasonal variability of chlorophyll-a and oceanographic conditions in Sabah waters in relation to Asian monsoon—a remote sensing study

Environmental Monitoring and Assessment ◽

10.1007/s10661-012-2843-2 ◽

2012 ◽

Vol 185 (5) ◽

pp. 3977-3991 ◽

Cited By ~ 11

Author(s):

Alaa Abdul-Hadi ◽

Shattri Mansor ◽

Biswajeet Pradhan ◽

C. K. Tan

Keyword(s):

Remote Sensing ◽

Chlorophyll A ◽

Seasonal Variability ◽

Asian Monsoon ◽

Oceanographic Conditions

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Tyrrhenian Upper Waters in the Ustica Island (Marine Protected Area, Sicily, Italy)

International Journal of Ecology ◽

10.1155/2009/161609 ◽

2009 ◽

Vol 2009 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Marilena Sanfilippo ◽

Giuseppa Pulicanò ◽

Antonio Manganaro ◽

Alessandra Reale ◽

Giuseppa Cortese

Keyword(s):

Dissolved Oxygen ◽

Chlorophyll A ◽

Seasonal Variability ◽

Protected Area ◽

Marine Protected Area ◽

Water Characteristics ◽

Atlantic Current

The Marine Protected Area (MPA) of Ustica was monitored for the hydrographic properties in the A zone of the reserve during the period from the autumn of 2001 to the winter of 2003. This study is also a part of a great triennal project (2001–2004) “Sistema Afrodite”, that was carried out in all the MPAs instituted in Italy. The parameters examined were treated statistically to show their seasonal variability. Temperature, nitrate, phosphate, and chlorophyll a showed similar trends between winter 2002 and 2003, while differences between winter 2002 and 2003 were noticed for salinity, dissolved oxygen, and silicate. It is postulated that the Atlantic current and eddies along its margin result in variation of the water characteristics in the MPA zone analyzed in this study.

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Seasonal and spatial variability of methane emissions from a subtropical reservoir in Eastern China

10.5194/bg-2018-195 ◽

2018 ◽

Cited By ~ 1

Author(s):

Le Yang ◽

Hepeng Li ◽

Chunlei Yue ◽

Jun Wang

Keyword(s):

Spatial Variability ◽

Time Scales ◽

Seasonal Variability ◽

Eastern China ◽

Methane Emissions ◽

Spatiotemporal Variability ◽

Ch4 Emission ◽

Atmospheric Methane ◽

Ch4 Flux ◽

Minimum Value

Abstract. Subtropical reservoirs are important source of atmospheric methane (CH4). This study aims to investigate the spatiotemporal variability of CH4 emission, using the methods of static floating chambers and bubble traps, from the water surfaces of Xin'anjiang Reservoir. Seasonal variability showed that CH4 emission from the main reservoir body was high in autumn and low in spring, with medium values in summer and winter. The dynamics of CH4 emission was flat from February to June, but fluctuated dramatically from July to January in the upstream river, which was interrupted by the bubbles in the second half year. However, CH4 emission was largely influenced by the streamflow in the downstream river, with a minimum value in February due to an extreme low streamflow (275 m3 s−1). Spatial variability showed the upstream river had the highest CH4 flux (3.90 ± 7.80 mg CH4 m−2 h−1), followed by the downstream river (0.50 ± 0.41 mg CH4 m−2 h−1), and the main reservoir body stood the last place (0.01 ± 0.07 mg CH4 m−2 h−1). Therefore, it was necessary to capture the variation of CH4 emission from reservoirs in the space and time scales to avoid the error of estimating the CH4 emission incorrectly.

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