scholarly journals Variations of net primary productivity and phytoplankton community composition in the Southern Ocean as estimated from ocean-color remote sensing data

2012 ◽  
Vol 9 (4) ◽  
pp. 4361-4398 ◽  
Author(s):  
S. Takao ◽  
T. Hirawake ◽  
S. W. Wright ◽  
K. Suzuki
Keyword(s):  
Remote Sensing ◽  
Southern Ocean ◽  
Community Composition ◽  
Primary Productivity ◽  
Phytoplankton Community ◽  
Net Primary Productivity ◽  
Austral Summer ◽  
Remote Sensing Data ◽  
The Past ◽  
Phytoplankton Community Composition

Abstract. Phytoplankton population dynamics play an important role in biogeochemical cycles in the Southern Ocean during austral summer. Recent environmental changes such as a rise in sea surface temperature (SST) are likely to impact on net primary productivity (NPP) and phytoplankton community composition. However, their spatiotemporal relationships are still unclear in the Southern Ocean. Here we assessed the relationships between NPP, dominant phytoplankton groups, and SST in the Indian sector of the Southern Ocean over the past decade (1997–2007) using satellite remote sensing data. As a result, we found a statistically significant reduction in NPP in the polar frontal zone over the past decade during austral summer. Moreover, the decrease in NPP positively correlated with the dominance of diatoms (Kendall's rank correlation τ = 0.60) estimated by a phytoplankton community composition model, but not correlated with SST. In the seasonal ice zone, NPP correlated with not only the dominance of diatoms positively (τ = 0.56), but also the dominance of haptophytes (τ = −0.54) and SST (τ = −0.54) negatively. Our results suggested that summer NPP values were strongly affected by the phytoplankton community composition in the Southern Ocean.

scholarly journals Variations of net primary productivity and phytoplankton community composition in the Indian sector of the Southern Ocean as estimated from ocean color remote sensing data

2012 ◽  
Vol 9 (10) ◽  
pp. 3875-3890 ◽  
Author(s):  
S. Takao ◽  
T. Hirawake ◽  
S. W. Wright ◽  
K. Suzuki
Keyword(s):  
Southern Ocean ◽  
Community Composition ◽  
Primary Productivity ◽  
Phytoplankton Community ◽  
Net Primary Productivity ◽  
Austral Summer ◽  
Remote Sensing Data ◽  
The Past ◽  
Phytoplankton Community Composition ◽  
Indian Sector

Abstract. Phytoplankton population dynamics play an important role in biogeochemical cycles in the Southern Ocean during austral summer. Recent environmental changes such as a rise in sea surface temperature (SST) are likely to impact on net primary productivity (NPP) and phytoplankton community composition. However, their spatiotemporal relationships are still unclear in the Southern Ocean. Here we assessed the relationships between NPP, dominant phytoplankton groups, and SST in the Indian sector of the Southern Ocean over the past decade (1997–2007) using satellite remote sensing data. As a result, we found a statistically significant reduction in NPP in the polar frontal zone over the past decade during austral summer. Moreover, the decrease in NPP positively correlated with the dominance of diatoms (Kendall's rank correlation τ = 0.60) estimated by a phytoplankton community composition model, but not correlated with SST. In the seasonal ice zone, NPP correlated with not only the dominance of diatoms positively (τ = 0.56), but also the dominance of haptophytes (τ = −0.54) and SST (τ = −0.54) negatively. Our results suggested that summer NPP values were strongly affected by the phytoplankton community composition in the Indian sector of the Southern Ocean.

Assessment on 2000-2010 Ecosystem Function Changes of Yiwulvshan National Nature Scenic Area

2014 ◽  
Vol 1051 ◽  
pp. 489-494
Author(s):  
Xiao Chen Wang ◽  
Jing Hai Zhu ◽  
Yuan Man Hu ◽  
Wei Ling Liu
Keyword(s):  
Remote Sensing ◽  
Ecosystem Function ◽  
Primary Productivity ◽  
Water Conservation ◽  
Net Primary Productivity ◽  
Remote Sensing Data ◽  
Vegetation Coverage ◽  
The Past ◽  
Remote Sensing Technology ◽  
Sensing Technology

Based on the remote-sensing data and ground data, this study is conducted on the ecosystem function of Yiwulvshan National Nature Scenic Area (hereinafter as “Yiwulvshan Scenic Area”) from 2000 to 2010 with the GIS (geographic information system) and RS (remote sensing) technology, so as to provide reference for better environmental protection of the scenic area. It is shown from the results that there is no obvious change of land use in Yiwulvshan Scenic Area; while the capacity for soil and water conservation is slightly improved mainly due to increase of vegetation coverage; the vegetation net primary productivity declines somewhat about 5.27% in past 10 years; and biodiversity is slightly increased. As a whole, the ecosystem function of Yiwulvshan Scenic Area basically kept stable in the past 10 years, which indicated that the existing regulations can effectively protect the ecological function of the Scenic Area.

scholarly journals Factors controlling coccolithophore biogeography in the Southern Ocean

2018 ◽  
Vol 15 (22) ◽  
pp. 6997-7024 ◽  
Author(s):  
Cara Nissen ◽  
Meike Vogt ◽  
Matthias Münnich ◽  
Nicolas Gruber ◽  
F. Alexander Haumann
Keyword(s):  
Southern Ocean ◽  
Phytoplankton Community ◽  
Net Primary Productivity ◽  
Austral Summer ◽  
Relative Importance ◽  
Biotic Factors ◽  
Top Down ◽  
Light Levels ◽  
Resolution Model ◽  
High Resolution Model

Abstract. The biogeography of Southern Ocean phytoplankton controls the local biogeochemistry and the export of macronutrients to lower latitudes and depth. Of particular relevance is the competitive interaction between coccolithophores and diatoms, with the former being prevalent along the “Great Calcite Belt” (40–60∘ S), while diatoms tend to dominate the regions south of 60∘ S. To address the factors controlling coccolithophore distribution and the competition between them and diatoms, we use a regional high-resolution model (ROMS–BEC) for the Southern Ocean (24–78∘ S) that has been extended to include an explicit representation of coccolithophores. We assess the relative importance of bottom-up (temperature, nutrients, light) and top-down (grazing by zooplankton) factors in controlling Southern Ocean coccolithophore biogeography over the course of the growing season. In our simulations, coccolithophores are an important member of the Southern Ocean phytoplankton community, contributing 17 % to annually integrated net primary productivity south of 30∘ S. Coccolithophore biomass is highest north of 50∘ S in late austral summer, when light levels are high and diatoms become limited by silicic acid. Furthermore, we find top-down factors to be a major control on the relative abundance of diatoms and coccolithophores in the Southern Ocean. Consequently, when assessing potential future changes in Southern Ocean coccolithophore abundance, both abiotic (temperature, light, and nutrients) and biotic factors (interaction with diatoms and zooplankton) need to be considered.

Spatio-temporal variation of net primary productivity in a rapidly expanding artificial woodland area based on remote-sensing data

Erdkunde ◽  
2021 ◽  
Vol 75 (3) ◽  
pp. 191-207
Author(s):  
Qi Yi ◽  
Yuting Gao ◽  
Hongrong Du ◽  
Junxu Chen ◽  
Liang Emlyn Yang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Cover ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Meteorological Data ◽  
Arable Land ◽  
Remote Sensing Data ◽  
Stand Age ◽  
Sensing Data ◽  
Spatio Temporal

The expansion of artificial woodlands in China has contributed significantly to regional land-cover changes and changes in the regional net primary productivity (NPP). This study used Ximeng County in the Yunnan Province as a case study to investigate the overall changes, associated amplitude, and spatio-temporal distribution of NPP from 2000–2015.The Carnegie-Ames-Stanford approach was used in the rapidly expanding artificial woodland area based on MODIS-NDVI data, meteorological data, and Landsat 5 TM data to calculate the NPP. The results show that (1) artificial woodlands experience a 10fold increase and account for 93 % of the land cover transfer, which was mainly from woodland areas. (2) The NPP was 906.2×109 gC·yr-1 in 2000 and 972.0×109 gC·yr-1 in 2015, presenting a total increase of 65.8×109 gC·yr-1 and a mean increase of 52.4 gC·m-2·yr-1 in Ximeng County. (3) The most notable NPP changes take place in the central and the western border regions, with the increasing NPP of artificial woodlands and arable land offsetting the negative effects of the decrease in woodland NPP. (4) The total NPP in the study area kept increasing, primarily due to the growing area of artificial woodlands as well as the stand age of the woods, whereas the mean value change of the NPP is mostly related to the increasing stand age. (5) The artificial woodlands increase the NPP value more than natural woodlands. While protecting and promoting ecologically valuable natural forests at the same time, it seems quite advantageous to establish regional plantations and coordinate their development on a scientific basis with a view to increasing NPP, economic development, but also the ecological stability of this mountain region. Our study reveals the changes in NPP and its distribution in a rapidly expanding area of artificial woodland in southwest China based on remote-sensing data and the CASA model, providing a decision-making basis for rational land-use management, the optimal utilization of land resources, and a county-scale assessment approach.

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