ISSN:
1573-5117
Keywords:
macrophytes
;
lakes
;
clarity
;
light attenuation
;
PAR
;
New Zealand
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The seasonal variation in water clarity, as indicated by the attenuation coefficient for photosynthetically active radiation, K d (m-1), was determined by monthly measurements for a year in 9 North Island, New Zealand lakes. K d varied by a factor of 2 to 3 in 8 of the lakes, and a factor of 5 in one. Annual mean K d (symbol% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa!36BD!\[K\] d) varied by a factor of approximately 15 between lakes. The maximum depth of water colonized by macrophytes (z c)was also determined. Values of z c were in the range 1.5–12.5 m. The relationship z c =4.34/% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa!36BD!\[K\]d accounted for most (93 percent) of the variability in z c , indicating that average annual clarity was probably a useful predictor of z c in lakes in this region. The values of z c in these North Island lakes were generally greater than values calculated using previously published empirical relationships derived for northern hemisphere groups of lakes. The extent to which these relationships underestimated z c in the North Island lakes was broadly related to latitude. Estimated average irradiance at z c in each lake was similar to compensation point irradiances reported previously for freshwater macrophytes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00004172
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