The Autecology of Eudiaptomus cf drieschi (Poppe & Mrazek 1895 ...

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Research Objectives The object of this research is to present documentation of the life cycle of the diaptomid copepod Eudiaptomus drieschi (Poppe & Mrazek 1895) in Lake Kinneret during the years 1994-2000, specifically, to follow population dynamics in the field by measuring secondary production, seasonal distribution patterns, and life stage development in the laboratory. Preliminary studies were conducted in 1994-95, and continuous monitoring began in 1996. Ontogenetic distribution, diel changes in the pelagic population, and benthic resting egg distribution are also investigated. Field observations in conjunction with laboratory measurements will be used to examine the temperature and salinity tolerances of E. drieschi. The physical and biological changes that have occurred in Lake Kinneret which have allowed for the invasion of this species to the pelagic regions of the lake will be discussed. A possible vector for resting egg distribution will be suggested.
1. General Introduction 1.1 Kinneret Background Lake Kinneret (32 0 42’ and 32 0 53’N) is located in northern Israel in the Syrian- African Rift Valley. It is a subtropical, monomictic lake, and the only natural freshwater lake in Israel (Gophen 1984, 1989). Mixing usually begins in early winter (December), and turnover is usually completed by mid- January, which means the lake is thermally stratified early summer through late fall (June-December). The lake surface area is 170 km 2 with a mean minimum depth of 24 m and maximum of 42 m when the lake level is at 209 m below Mean Sea Level. The average yearly temperatures range from 14 0 C to 30 0 C. Historically, the lake level has been seen to vary widely from -212 m to -209 m. Currently, due to consecutive drought years, the lake is at a previously unrecorded low level of –214.23. The lake is situated at the boundary of semi-arid and moist climatic conditions. As a result, there are strong seasonal patterns of wind and rainfall in the lake area. The amount of rainfall throughout the winter period (October-April) is highly variable and not uniform across the lake. The monthly average wind speeds are higher in summer than in winter, and winter winds are predominantly from the east, while summer winds are from the west. Two periods of “weak wind” generally occur in spring and autumn (Serruya 1978). The external winds in conjunction with the internal temperature regime greatly influence water movement. A thermal gradient, some 2-3 0 C difference from the surrounding waters, begins to develop during the spring (March–April) which generates a changeable barrier (thermocline) in the upper water body (8-10 m). Below this barrier, oxygen and pH begin to decrease and CO 2 is present on the bottom. Towards the summer, the increased warming causes the thermocline to deepen which effectively
Page 1 and 2: The Autecology of Eudiaptomus cf dr
Page 3 and 4: Table of Contents Page Abstract Res
Page 5 and 6: Abstract Prior to the mid-eighties,
Page 7: occupying a niche and using its ada
Page 11 and 12: Over 30 different zooplankton speci
Page 13 and 14: The National Water Carrier, which w
Page 15 and 16: (Baird 1859); Arctodiaptomus (Arcto
Page 17 and 18: 2. Methods and Materials 2.1 Season
Page 19 and 20: (>20 µm) and nano (20 m) and nano
Page 21 and 22: Stock preparations Females with rip
Page 23 and 24: when the population meets condition
Page 25 and 26: 2.4.4. Food Requirements Mature adu
Page 27 and 28: c) b) a) d) e) • Figure 2: a) fem
Page 29 and 30: 23 The female antennules are symmet
Page 31 and 32: 25 Monthly Copepod Biomass 25.0 20.
Page 33 and 34: E. drieschi has a strong seasonal p
Page 35 and 36: Total Number of Organisms, L -1 80
Page 37 and 38: decline of E. drieschi in the water
Page 39 and 40: Average Depth of Individual = x 1 z
Page 41 and 42: Resting Egg Distribution in the Sed
Page 43 and 44: ) c) Figure 14: (a) resting egg fro
Page 45 and 46: 3.6 Development Development Time De
Page 47 and 48: Development Rate Post-embryonic dev
Page 49 and 50: 3.7 Salinity tolerance Survival of
Page 51 and 52: 4. Discussion 4.1 Taxonomical Posit
Page 53 and 54: 4.2 Ecological Implications of Deve
Page 55 and 56: seasonal abundance or intra-specifi
Page 57 and 58: distinguish resting eggs from subit
Page 59 and 60:
ability as copepods mature. Diaptom
Page 61 and 62:
4.5.2 Temperature Temperature has b
Page 63 and 64:
4.5.3 Food Calanoid copepods in gen
Page 65 and 66:
chloride. Between 1955-69, salinity
Page 67 and 68:
This study offered the rare (and fo
Page 69 and 70:
Beeton, A. M. (1981) General introd
Page 71 and 72:
DeFrenza, J., Kirner, R.J., Maly, E
Page 73 and 74:
Gophen, M. 1977. Food and feeding h
Page 75 and 76:
Hanazato, T. and Yasuno, M. 1989. I
Page 77 and 78:
Kawabata, K. 1989. Natural developm
Page 79 and 80:
Norrbin, M.F. 1994. Seasonal patter
Page 81 and 82:
copepod species in the eastern Wedd
Page 83 and 84:
Implications for diel vertical migr
Page 85 and 86:
האאוטאקולוגיה של (Po
Page 87 and 88:
והוטלו שנה קודם לכך
Page 89:
האאוטאקולוגיה של (Po
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