Simulated in situ growth rates of pelagic marine bacteria

1978 ◽  
Vol 65 (10) ◽  
pp. 541-542 ◽  
Author(s):  
A. F. Carlucci ◽  
P. M. Williams
Keyword(s):  
Marine Bacteria ◽  
Growth Rates ◽  
In Situ Growth

In situ growth rates of deep-water octocorals determined from 3D photogrammetric reconstructions

Coral Reefs ◽  
2016 ◽  
Vol 35 (4) ◽  
pp. 1227-1239 ◽  
Author(s):  
Swaantje Bennecke ◽  
Tom Kwasnitschka ◽  
Anna Metaxas ◽  
Wolf-Christian Dullo
Keyword(s):  
Deep Water ◽  
Growth Rates ◽  
In Situ Growth

scholarly journals Continuous in situ measurements of anchor ice formation, growth and release

2020 ◽  
Author(s):  
Tadros R. Ghobrial ◽  
Mark R. Loewen
Keyword(s):  
Crystal Growth ◽  
Water Column ◽  
Growth Rates ◽  
Ice Formation ◽  
Formation Mechanisms ◽  
In Situ Growth ◽  
River Bed ◽  
Anchor Ice ◽  
Stage 1

Abstract. In northern rivers, turbulent water becomes supercooled (i.e. cooled to slightly below 0 °C) when exposed to freezing air temperatures. In supercooled water, frazil (small ice disks) crystals are generated in the water column and anchor ice starts to form on the bed. Two anchor ice formation mechanisms have been reported in the literature: either by the accumulation of suspended frazil particles, which are adhesive (sticky) in nature, on the river bed; or by in situ growth of ice crystals on the bed material. Once anchor ice has formed on the bed, the accumulation typically continues to grow (either due to further frazil accumulation and/or crystal growth) until release occurs due to mechanical (shear force by the flow or buoyancy of the accumulation) or thermal (warming of the water column which weakens the ice-substrate bond) forcing or a combination of the two. Although detailed laboratory experiments have been reported to study anchor ice, but very few field measurements of anchor ice processes have been reported. These measurements have relied on either sampling anchor ice accumulations from the river bed, or qualitatively describing the observed formation and release. In this study, a custom-built imaging system (camera and lighting) was developed to capture high-resolution digital images of anchor ice formation and release on the river bed. A total of six anchor ice events were successfully captured in the time-lapse images and for the first time, the different initiation, growth and release mechanisms were measured in the field. Four stages of the anchor ice cycle were identified, namely: Stage 1: initiation by in situ crystal growth, Stage 2: transitional phase, Stage 3: linear growth, and Stage 4: release phase. Anchor ice initiation due to in situ growth was observed in three events and in the remainder the accumulation appeared to be initiated by frazil deposition. The Stage 1 growth rates ranged from 1.3 to 2.0 cm/hr and the Stage 2 and 3 growth rates varied from 0.3 to 0.9 cm/hr. Anchor ice was observed releasing from the bed in three modes referred to as lifting, shearing and rapid.

scholarly journals Continuous in situ measurements of anchor ice formation, growth, and release

2021 ◽  
Vol 15 (1) ◽  
pp. 49-67
Author(s):  
Tadros R. Ghobrial ◽  
Mark R. Loewen
Keyword(s):  
Crystal Growth ◽  
Water Column ◽  
Growth Rates ◽  
Ice Formation ◽  
Formation Mechanisms ◽  
In Situ Growth ◽  
Anchor Ice ◽  
Stage 1 ◽  
Turbulent Water

Abstract. In northern rivers, turbulent water becomes supercooled (i.e. cooled to slightly below the freezing point) when exposed to freezing air temperatures. In supercooled turbulent water, frazil (small ice disks) crystals are generated in the water column, and anchor ice starts to form on the bed. Two anchor ice formation mechanisms have been reported in the literature: either by the accumulation of suspended frazil particles, which are adhesive (sticky) in nature, on the riverbed or by in situ growth of ice crystals on the bed material. Once anchor ice has formed on the bed, the accumulation typically continues to grow (due to either further frazil accumulation and/or crystal growth) until release occurs due to mechanical (shear force by the flow or buoyancy of the accumulation) or thermal (warming of the water column which weakens the ice-substrate bond) forcing or a combination of the two. There have been a number of detailed laboratory studies of anchor ice reported in the literature, but very few field measurements of anchor ice processes have been reported. These measurements have relied on either sampling anchor ice accumulations from the riverbed or qualitatively describing the observed formation and release. In this study, a custom-built imaging system (camera and lighting) was developed to capture high-resolution digital images of anchor ice formation and release on the riverbed. A total of six anchor ice events were successfully captured in the time-lapse images, and for the first time, the different initiation, growth, and release mechanisms were measured in the field. Four stages of the anchor ice cycle were identified: Stage 1: initiation by in situ crystal growth; Stage 2: transitional phase; Stage 3: linear growth; and Stage 4: release phase. Anchor ice initiation due to in situ growth was observed in three events, and in the remainder, the accumulation appeared to be initiated by frazil deposition. The Stage 1 growth rates ranged from 1.3 to 2.0 cm/h, and the Stage 2 and 3 growth rates varied from 0.3 to 0.9 cm/h. Anchor ice was observed releasing from the bed in three modes: lifting of the entire accumulation, shearing of layers of the accumulation, and rapid release of the entire accumulation.

Application of photopigment biomarkers for quantifying microalgal community composition and in situ growth rates

2001 ◽  
Vol 32 (4) ◽  
pp. 585-595 ◽  
Author(s):  
James L Pinckney ◽  
Tammi L Richardson ◽  
David F Millie ◽  
Hans W Paerl
Keyword(s):  
Community Composition ◽  
Growth Rates ◽  
In Situ Growth ◽  
Microalgal Community
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