Experimental Mesocosm Study of the Separate and Interaction Effects of Phosphorus and Mosquitofish (Gambusia affinis) on Plankton Community Structure

1990 ◽  
Vol 47 (3) ◽  
pp. 471-479 ◽  
Author(s):  
Holli F. Lancaster ◽  
Ray W. Drenner

We examined community impacts of phosphorus and mosquitofish (Gambusia affinis) in an experimental mesocosm study of factorial design in which two levels of phosphorus addition were cross-classified with two levels of fish. Total phosphorus (TP), chlorophyll, cryptomonads, unicellular green algae, unicellular blue-green algae, colonial blue-green algae, filamentous blue-green algae, chironomid tube length, cladocerans, fish density, and fish biomass were significantly enhanced in the presence of phosphorus addition. Total nitrogen (TN), TN:TP ratio, Secchi depth, chrysophytes, and periphytic diatoms were suppressed in the presence of phosphorus addition. Diatoms, filamentous blue-green algae, chrysophytes, periphytic unicellular and colonial green algae, periphytic filamentous blue-green algae, and rotifers were enhanced in the presence of mosquitofish. Secchi depth, TN:TP ratio, cyclopoid copepodids, nauplii, cladocerans, and chironomid tubes were suppressed in the presence of mosquitofish. We found significant phosphorus × mosquitofish interaction effects for TN:TP ratio, chrysophytes, dinoflagellates, periphytic colonial green algae, cladocerans, and chironomid tubes. These results show that nutrients and fish do not act as independent regulators of plankton communities but instead have effects which can only be predicted from an understanding of their combined impacts.

1982 ◽  
Vol 14 (4-5) ◽  
pp. 397-406 ◽  
Author(s):  
H Bernhardt ◽  
J Clasen

The elimination of the phosphorus compounds from the River Wahnbach (100 - 150 µg/l Ptot) at the point where it flows into the Wahnbach Reservoir down to a figure of 5 µg/l Ptot has decreased the total phosphorus concentration in the Wahnbach Reservoir to 8 - 10 µg/l Ptot. As a result of this, the impoundment which had been in an eutrophic state became oligotrophic to mesotrophic within 3 years. The blue-green algae which had been predominant disappeared and diatoms grow again every spring. Algal growth has been reduced to such an extent that the transparency has gone up to a Secchi-depth of 10 m and was 6 m on an annual average. This was solely produced by eliminating phosphorus and without eliminating nitrogen at the same time (the annual average N-concentration of all tributaries was 5 mg/l).


Author(s):  
L. V. Leak

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.


2017 ◽  
Vol 40 (1) ◽  
pp. 47-62 ◽  
Author(s):  
I. M. Chung ◽  
S. H. Kim ◽  
Y.T. Oh ◽  
M. Ali ◽  
A. Ahmad

2009 ◽  
Vol 33 (5) ◽  
pp. 860-865
Author(s):  
Lan-Lan LU ◽  
Gen-Bao LI ◽  
Yin-Wu SHEN ◽  
Ming-Ming HU ◽  
Yong-Ding LIU

1995 ◽  
Vol 31 (11) ◽  
pp. 153-158 ◽  
Author(s):  
M. Kajino ◽  
K. Sakamoto

Musty odor has occurred annually in Lake Biwa since 1969. Osaka municipal waterworks, which is located downstream of Lake Biwa, has made many efforts to treat musty-odor compounds produced in Lake Biwa from spring through autumn. With the development of analytical methods for the determination of musty-odor compounds, we have been able to confirm that planktonic blue-green algae are the major causes of the musty-odor occurrences. The relationship between the growth of blue-green algae and the water quality was not so apparent. However, through our data analysis focusing on the relationship between musty-odor occurrences due to Phormidium tenue or Oscillatoria tenuis and some nutrients in Lake Biwa, we found that the concentration of nitrate in water may be an important parameter for the estimation of growth of the algae and the musty-odor behavior.


2017 ◽  
Vol 24 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Rashmi Chandra ◽  
Roberto Parra ◽  
Hafiz M. N. Iqbal

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