Seasonal changes in the vertical distribution of mesozooplankton in the Greenland Sea Gyre (75°N): distribution strategies of calanoid copepods

AbstractOur observations indicate the vertical distribution of zooplankton and its seasonal changes in Dubník II reservoir (Slovakia) are determined mainly by the thermal regime of the reservoir, by transparency, and by fish and invertebrate predation. During periods of circulation, zooplankton vertical distribution in the whole water column was more homogeneous, whilst during summer temperature stratification zooplankton concentrated in the epilimnion — rotifers in higher layers than crustaceans. During summer stagnation a steep thermal gradient occurred at the boundary of the epi-and hypolimnion and low temperature and low dissolved oxygen in hypolimnion offered a refuge for Chaoborus flavicans larvae against fish, enabling coexistence of vertebrate and invertebrate predation. This evidence supports our previous findings concerning dominance of rotifers in zooplankton and representation of crustaceans by small-bodied species in the study reservoir. Steep thermal gradient and the presence of Chaoborus larvae caused very low zooplankton abundance in the lower part of the water column and a reduction of cladocerans refuges against fish to layers of thermocline or closely under thermocline where Daphnia cucullata and Daphnia parvula were found. Our previous assumptions about the high density of zooplanktivorous fish in Dubník II reservoir are supported by the fact that these small cladocerans are represented by smaller individuals in the upper layers and bigger individuals in deeper layers.

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Spatial changes in the vertical distribution of calanoid copepods down to great depths in the North Pacific

Zoological Studies ◽

10.1186/s40555-014-0091-6 ◽

2015 ◽

Vol 54 (1) ◽

Cited By ~ 7

Author(s):

Atsushi Yamaguchi ◽

Kohei Matsuno ◽

Tomoe Homma

Keyword(s):

Vertical Distribution ◽

North Pacific ◽

Calanoid Copepods ◽

The North ◽

Spatial Changes ◽

The Vertical Distribution ◽

The North Pacific

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CONGENERIC OCCURRENCES OF SPECIES OF DIAPTOMUS IN SOUTHERN ONTARIO LAKES

Canadian Journal of Zoology ◽

10.1139/z67-010 ◽

1967 ◽

Vol 45 (1) ◽

pp. 81-90 ◽

Cited By ~ 17

Author(s):

F. H. Rigler ◽

R. R. Langford

Keyword(s):

Vertical Distribution ◽

Calanoid Copepods ◽

Southern Ontario ◽

Ecological Separation ◽

The Difference ◽

Limnocalanus Macrurus ◽

The Vertical Distribution

The vertical distribution of adult calanoid copepods was studied in 100 lakes in southern Ontario. In addition to Epischura lacustris, Limnocalanus macrurus, and Senecella calanoides, seven species of Diaptomus were recorded. Diaptomus minutus and D. oregonensis, the commonest species, coexisted in 45% of the lakes. In 9% a third species was also present. Coexisting populations of D. minutus and D. oregonensis were not well separated by their vertical distribution, but a third species, if present, occurred in deeper water than these two. Size displacement does not contribute to the ecological separation of D. minutus and D. oregonensis. The difference in size between populations coexisting in the same lake is less than between populations living in separate lakes.

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Vertical Distribution of Xiphinemabakeri Nematodes in Soil in a Douglas-fir Nursery

Canadian Journal of Forest Research ◽

10.1139/x74-026 ◽

1974 ◽

Vol 4 (2) ◽

pp. 175-178

Author(s):

Jack R. Sutherland

Keyword(s):

Moisture Content ◽

Vertical Distribution ◽

Distribution Pattern ◽

Seasonal Changes ◽

Root Distribution ◽

Pore Space ◽

Douglas Fir ◽

Soil Samples ◽

Nematode Control ◽

The Vertical Distribution

Soil samples were collected throughout the year to determine the vertical distribution of Xiphinemabakeri nematodes in soil in a Douglas-fir [Pseudotsugamenziesii (Mirb.) Franco] nursery and to monitor seasonal changes in nematode distribution pattern. Root distribution, moisture content, available pore space, and osmotic pressure were also determined for soil samples taken at various depths to see if they were related to nematode distribution. More than 90% of the nematodes were present in the upper 20 cm of soil, especially from 0 to 10 cm, and this percentage did not change with season. Nematode distribution was related only to root distribution. The significance of the results for nematode control practices is discussed.

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A re-examination of Calanus collected off Plymouth

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400012790 ◽

1951 ◽

Vol 30 (2) ◽

pp. 313-314 ◽

Cited By ~ 5

Author(s):

F. S. Russell

Keyword(s):

Vertical Distribution ◽

Seasonal Changes ◽

Calanus Finmarchicus ◽

Future Research ◽

The Subject ◽

The Vertical Distribution ◽

Representative Samples ◽

Biological Differences ◽

Distinguishing Character ◽

Made In

Rees (1949) has established significant biological differences between the two forms of the copepod Calanus finmarchicus, namely finmarchicus and helgolandicus. It is therefore necessary that in future research on the behaviour of Calanus the two forms should be distinguished.I have myself published observations on the vertical distribution of Calanus and on the seasonal changes in size of individuals of the populations of this copepod off Plymouth. In order to know whether my results have been vitiated by the presence of the two forms in the collections, I have re-examined representative samples of adult females, using the fifth leg as the distinguishing character. The collections in question were those made in 1926 which formed the subject of a paper on seasonal changes in vertical distribution and in the sizes of individuals of different generations (Russell, 1928); and those made in 1931 and recorded in my paper on the vertical distribution of Calanus in relation to light intensity (Russell, 1934).

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