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Temporal and spatial variations in phytoplankton productivity and related factors in the surface waters of Kaneohe Bay, Oahu, Hawaii

Data on primary productivity, chlorophyll a, nitrate,
and phosphate in surface waters were collected on a 14-month (March, 1970 to April, 1971) series of approximately
biweekly cruises in Kaneohe Bay, Oahu, Hawaii. During the latter part of the survey data ammonium ion concentrations
and light penetration through the water column were
also collected. The year is divided into two seasons on
the basis of rainfall, and the effects on the dynamics of
the phytoplankton community of terrestrial runoff and
sewage effluents entering the bay are separated on the
basis of differences between wet season and dry season
productivity indices (productivity/Chl. a). The bay is
divided into three sectors; South, Transition, and North.
The most important nutrient sources are; the Kaneohe
Municipal Sewage Treatment Plant effluent to the South
Sector, terrestrial runoff to the Transition Sector, and a
persistent, but unidentified nitrate input to the North
Sector. The Municipal Treatment Plant effluent is shown
to be toxic to phytoplankton in the immediate area.
Phosphate concentration is not correlated with rainfall,
and is present in non-limiting concentrations in all
sectors. Nitrate concentration is strongly correlated with
rainfall in the Transition Sector, and low dry season
(summer) concentrations may limit phytoplankton growth.
Wet season (winter) nitrate concentrations in the other two sectors are also higher than summer values, but the differences
are not significant. Fluctuations in phytoplankton
population size seem to be primarily a function of
variable grazing pressure by herbivorous zooplankton.
Phytoplankton growth rates peak in summer and winter, and
may be related to the availability of light. Light penetration itself
is directly related to phytoplankton
density in the water column, and the winter growth rate
peak may result from increasing light penetration due to
extensive grazing on the phytoplankton population. The
present data are compared with similar data collected 10
years earlier. Based on a hyperbolic relationship between
substrate concentration and growth rate, the South Sector
is shown to have been eutrophic for at least the past
decade, while in the Transition and North Sectors symptoms
of eutrophication have appeared during this decade. / Typescript. Theses for the degree of Master of Science (University of Hawaii at Manoa)--University of Hawaii, 1973. Bibliography: leaves 87-90.

Identiferoai:union.ndltd.org:UHAWAII/oai:scholarspace.manoa.hawaii.edu:10125/15307
Date20 April 2010
CreatorsKrasnick, George J
Source SetsUniversity of Hawaii at Manoa Libraries
Languageen-US
Detected LanguageEnglish
TypeThesis, Text
Format97 pages
RightsAll UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.

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