Turbidity changes caused by collapse of cyanobacterial gas vesicles in water pumped from Lake Kinneret into the Israeli National Water Carrier

R. Porat; B. Teltsch; R. A. Mosse; Z. Dubinsky; A. E. Walsby

doi:10.1016/s0043-1354(98)00393-5

Turbidity changes caused by collapse of cyanobacterial gas vesicles in water pumped from Lake Kinneret into the Israeli National Water Carrier

R. Porat, B. Teltsch, R. A. Mosse, Z. Dubinsky, A. E. Walsby

The Mina and Everard Goodman Faculty of Life Sciences

Research output: Contribution to journal › Article › peer-review

15 Scopus citations

Abstract

The cyanobacterium Aphanizomenon ovalispormn Forti appeared in Lake Kinneret for the first time in the summer and autumn of 1994 and reappeared in 1995-1997. In 1994 it formed a large bloom (6000 filaments ml^-1) that caused high turbidity (up to 7 NTU), which is attributed mainly to light scattering by gas vesicles. When lake water was pumped into the high-pressure pipe (2.5 MPa) of the Israeli National Water Carrier (INWC) the turbidity of the water decreased by 65%, the Aphanizomenon filaments lost their buoyancy and some filaments fragmented. Application of 0.6 MPa pressure to cultures of the Lake Kinneret strain of A. ovalisporum in a pressure nephelometer caused collapse of all gas vesicles; the turbidity decreased by 80% and all of the filaments sedimented. The mean critical collapse pressure of the gas vesicles (p_c) was 0.58±20.02 MPa (with cells suspended in hypertonic sucrose solution), the apparent mean critical collapse pressure (p_c) was 0.27±0.02 MPa (with cells suspended in culture medium) and the mean turgor pressure (p_t) was 0.33±0.02 MPa. The value of p_a is lower than the pressures in any of the five high-pressure pipes (0.6-2.5 MPa) along the INWC. It is concluded that gas vesicle collapse caused the observed decrease in turbidity in the system. The combined physical, chemical and biological treatments given in the INWC system resulted in a 99.9% decrease in the A. ovalisporum biomass.

Original language	English
Pages (from-to)	1634-1644
Number of pages	11
Journal	Water Research
Volume	33
Issue number	7
DOIs	https://doi.org/10.1016/s0043-1354(98)00393-5
State	Published - May 1999

Bibliographical note

Funding Information:
We would like to thank Dr Ora Hadas for supplying the culture and for useful comments on the manuscript. We also thank Dr Asaf Sukenik for reviewing the manuscript and Tim Colburn for drawing Fig. 1 . This work was supported by Mekorot, the National Water Company of Israel and by a travel grant from the British Council to AEW. It forms part of R. P.'s Ph.D. dissertation at Bar-Ilan University.

Funding

We would like to thank Dr Ora Hadas for supplying the culture and for useful comments on the manuscript. We also thank Dr Asaf Sukenik for reviewing the manuscript and Tim Colburn for drawing Fig. 1 . This work was supported by Mekorot, the National Water Company of Israel and by a travel grant from the British Council to AEW. It forms part of R. P.'s Ph.D. dissertation at Bar-Ilan University.

Funders	Funder number
National Water Company of Israel
British Council

Keywords

Aphanizomenon ovalisporum
Cyanobacteria
Gas vesicles
Hydrostatic pressure
Israeli National Water Carrier
Lake Kinneret

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10.1016/s0043-1354(98)00393-5

Cite this

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title = "Turbidity changes caused by collapse of cyanobacterial gas vesicles in water pumped from Lake Kinneret into the Israeli National Water Carrier",

abstract = "The cyanobacterium Aphanizomenon ovalispormn Forti appeared in Lake Kinneret for the first time in the summer and autumn of 1994 and reappeared in 1995-1997. In 1994 it formed a large bloom (6000 filaments ml-1) that caused high turbidity (up to 7 NTU), which is attributed mainly to light scattering by gas vesicles. When lake water was pumped into the high-pressure pipe (2.5 MPa) of the Israeli National Water Carrier (INWC) the turbidity of the water decreased by 65%, the Aphanizomenon filaments lost their buoyancy and some filaments fragmented. Application of 0.6 MPa pressure to cultures of the Lake Kinneret strain of A. ovalisporum in a pressure nephelometer caused collapse of all gas vesicles; the turbidity decreased by 80% and all of the filaments sedimented. The mean critical collapse pressure of the gas vesicles (pc) was 0.58±20.02 MPa (with cells suspended in hypertonic sucrose solution), the apparent mean critical collapse pressure (pc) was 0.27±0.02 MPa (with cells suspended in culture medium) and the mean turgor pressure (pt) was 0.33±0.02 MPa. The value of pa is lower than the pressures in any of the five high-pressure pipes (0.6-2.5 MPa) along the INWC. It is concluded that gas vesicle collapse caused the observed decrease in turbidity in the system. The combined physical, chemical and biological treatments given in the INWC system resulted in a 99.9% decrease in the A. ovalisporum biomass.",

keywords = "Aphanizomenon ovalisporum, Cyanobacteria, Gas vesicles, Hydrostatic pressure, Israeli National Water Carrier, Lake Kinneret",

author = "R. Porat and B. Teltsch and Mosse, {R. A.} and Z. Dubinsky and Walsby, {A. E.}",

note = "Funding Information: We would like to thank Dr Ora Hadas for supplying the culture and for useful comments on the manuscript. We also thank Dr Asaf Sukenik for reviewing the manuscript and Tim Colburn for drawing Fig. 1 . This work was supported by Mekorot, the National Water Company of Israel and by a travel grant from the British Council to AEW. It forms part of R. P.'s Ph.D. dissertation at Bar-Ilan University.",

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AU - Porat, R.

AU - Teltsch, B.

AU - Mosse, R. A.

AU - Dubinsky, Z.

AU - Walsby, A. E.

N1 - Funding Information: We would like to thank Dr Ora Hadas for supplying the culture and for useful comments on the manuscript. We also thank Dr Asaf Sukenik for reviewing the manuscript and Tim Colburn for drawing Fig. 1 . This work was supported by Mekorot, the National Water Company of Israel and by a travel grant from the British Council to AEW. It forms part of R. P.'s Ph.D. dissertation at Bar-Ilan University.

PY - 1999/5

Y1 - 1999/5

N2 - The cyanobacterium Aphanizomenon ovalispormn Forti appeared in Lake Kinneret for the first time in the summer and autumn of 1994 and reappeared in 1995-1997. In 1994 it formed a large bloom (6000 filaments ml-1) that caused high turbidity (up to 7 NTU), which is attributed mainly to light scattering by gas vesicles. When lake water was pumped into the high-pressure pipe (2.5 MPa) of the Israeli National Water Carrier (INWC) the turbidity of the water decreased by 65%, the Aphanizomenon filaments lost their buoyancy and some filaments fragmented. Application of 0.6 MPa pressure to cultures of the Lake Kinneret strain of A. ovalisporum in a pressure nephelometer caused collapse of all gas vesicles; the turbidity decreased by 80% and all of the filaments sedimented. The mean critical collapse pressure of the gas vesicles (pc) was 0.58±20.02 MPa (with cells suspended in hypertonic sucrose solution), the apparent mean critical collapse pressure (pc) was 0.27±0.02 MPa (with cells suspended in culture medium) and the mean turgor pressure (pt) was 0.33±0.02 MPa. The value of pa is lower than the pressures in any of the five high-pressure pipes (0.6-2.5 MPa) along the INWC. It is concluded that gas vesicle collapse caused the observed decrease in turbidity in the system. The combined physical, chemical and biological treatments given in the INWC system resulted in a 99.9% decrease in the A. ovalisporum biomass.

AB - The cyanobacterium Aphanizomenon ovalispormn Forti appeared in Lake Kinneret for the first time in the summer and autumn of 1994 and reappeared in 1995-1997. In 1994 it formed a large bloom (6000 filaments ml-1) that caused high turbidity (up to 7 NTU), which is attributed mainly to light scattering by gas vesicles. When lake water was pumped into the high-pressure pipe (2.5 MPa) of the Israeli National Water Carrier (INWC) the turbidity of the water decreased by 65%, the Aphanizomenon filaments lost their buoyancy and some filaments fragmented. Application of 0.6 MPa pressure to cultures of the Lake Kinneret strain of A. ovalisporum in a pressure nephelometer caused collapse of all gas vesicles; the turbidity decreased by 80% and all of the filaments sedimented. The mean critical collapse pressure of the gas vesicles (pc) was 0.58±20.02 MPa (with cells suspended in hypertonic sucrose solution), the apparent mean critical collapse pressure (pc) was 0.27±0.02 MPa (with cells suspended in culture medium) and the mean turgor pressure (pt) was 0.33±0.02 MPa. The value of pa is lower than the pressures in any of the five high-pressure pipes (0.6-2.5 MPa) along the INWC. It is concluded that gas vesicle collapse caused the observed decrease in turbidity in the system. The combined physical, chemical and biological treatments given in the INWC system resulted in a 99.9% decrease in the A. ovalisporum biomass.

KW - Aphanizomenon ovalisporum

KW - Cyanobacteria

KW - Gas vesicles

KW - Hydrostatic pressure

KW - Israeli National Water Carrier

KW - Lake Kinneret

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SN - 0043-1354

VL - 33

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JO - Water Research

JF - Water Research

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ER -

Turbidity changes caused by collapse of cyanobacterial gas vesicles in water pumped from Lake Kinneret into the Israeli National Water Carrier

Abstract

Bibliographical note

Funding

Keywords

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