scholarly journals A statistical procedure for unsupervised classification of nutrient limitation bioassay experiments with natural phytoplankton communities

2007 ◽  
Vol 5 (4) ◽  
pp. 111-118 ◽  
Author(s):  
Tom Andersen ◽  
Tuomo M. Saloranta ◽  
Timo Tamminen
Keyword(s):  
Nutrient Limitation ◽  
Unsupervised Classification ◽  
Statistical Procedure ◽  
Phytoplankton Communities ◽  
Natural Phytoplankton

scholarly journals Nutrient Patchiness, Phytoplankton Surge-Uptake, and Turbulent History: A Theoretical Approach and Its Experimental Validation

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 80
Author(s):  
Mathilde Schapira ◽  
Laurent Seuront
Keyword(s):  
Nutrient Limitation ◽  
Inorganic Nitrogen ◽  
Small Scale ◽  
Nutrient Distribution ◽  
Heterogeneous Distribution ◽  
Ample Evidence ◽  
Phytoplankton Communities ◽  
High Turbulence ◽  
Natural Phytoplankton ◽  
Phytoplankton Cells

Despite ample evidence of micro- and small-scale (i.e., millimeter- to meter-scale) phytoplankton and zooplankton patchiness in the ocean, direct observations of nutrient distributions and the ecological importance of this phenomenon are still relatively scarce. In this context, we first describe a simple procedure to continuously sample nutrients in surface waters, and subsequently provide evidence of the existence of microscale distribution of ammonium in the ocean. We further show that ammonium is never homogeneously distributed, even under very high conditions of turbulence. Instead, turbulence intensity appears to control nutrient patchiness, with a more homogeneous or a more heterogeneous distribution observed under high and low turbulence intensities, respectively, under the same concentration in nutrient. Based on a modelling procedure taking into account the stochastic properties of intermittent nutrient distributions and observations carried out on natural phytoplankton communities, we introduce and verify the hypothesis that under nutrient limitation, the “turbulent history” of phytoplankton cells, i.e., the turbulent conditions they experienced in their natural environments, conditions their efficiency to uptake ephemeral inorganic nitrogen patches of different concentrations. Specifically, phytoplankton cells exposed to high turbulence intensities (i.e., more homogeneous nutrient distribution) were more efficient to uptake high concentration nitrogen pulses (2 µM). In contrast, under low turbulence conditions (i.e., more heterogeneous nutrient distribution), uptake rates were higher for low concentration nitrogen pulses (0.5 µM). These results suggest that under nutrient limitation, natural phytoplankton populations respond to high turbulence intensities through a decrease in affinity for nutrients and an increase in their transport rate, and vice versa.

Photoacclimation of natural phytoplankton communities

2016 ◽  
Vol 542 ◽  
pp. 51-62 ◽  
Author(s):  
JR Graff ◽  
TK Westberry ◽  
AJ Milligan ◽  
MB Brown ◽  
G Dall’Olmo ◽  
...  
Keyword(s):  
Phytoplankton Communities ◽  
Natural Phytoplankton

Unsupervised classification of street architectures based on InfoGAN

2019 ◽  
Author(s):  
Ning Wang ◽  
Xianhan Zeng ◽  
Renjie Xie ◽  
Zefei Gao ◽  
Yi Zheng ◽  
...  
Keyword(s):  
Unsupervised Classification

Unsupervised classification of MSS Landsat data for mapping spatially complex vegetation

1980 ◽  
Vol 1 (2) ◽  
pp. 105-120 ◽  
Author(s):  
John R. G. Townshend ◽  
Christopher O. Justice
Keyword(s):  
Unsupervised Classification ◽  
Landsat Data

Identification of carbon quantifiable regions in the former Soviet Union using unsupervised classification of AVHRR global vegetation index images

1994 ◽  
Vol 15 (16) ◽  
pp. 3199-3221 ◽  
Author(s):  
G. G. GASTON ◽  
P. L. JACKSON ◽  
T. S. VINSON ◽  
T. P. KOLCHUGINA ◽  
M. BOTCH ◽  
...  
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Vegetation Index ◽  
Unsupervised Classification ◽  
Global Vegetation
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