Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
turned to a bluish clear color with blue color
precipitate floating in the water.
Conc of N (ppm)
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
low
high
Figure 1. There was no difference in nitrate concentration
between low tide (1.07 ± 0.3 ppm (± se) and high tide (1.5
± 0.1 ppm (± se), (p = 0.1, one tailed t- test). Error bars
show the standard error.
1
Conc of P (ppm)
0.8
0.6
0.4
0.2
0
low
high
Figure 2. Phosphate concentration was greater during
high tide (0.77 ± 0.09 ppm (± se) than low tide ( 0.28 ±
0.02 ppm (± se,) (p= 0.02, one-tailed t-test). Error bars
indicate the standard error.
Discussion
For nitrate ion concentration was 1.07 ± 0.3
ppm (± se) at low tide and 1.5 ± 0.1 ppm (± se) at
high tide. Although hypothesis stated that nitrate ion
concentration and the tide level were corresponding,
the difference of nitrogen gas concentration at low
tide and high tide were not significant. The
concentration of nitrogen did not depend on the level
of tide in this study. The result may suggest that
dissolved nitrogen gas concentration varies
depending on the season of the year or water
conditions; for example salinity, temperature and
tides.
In this study, the phosphate concentration
showed the relatively high value. For phosphate
concentration, it was 0.3 ± 0.02 ppm (± se) at low
tide and was 0.77 ± 0.09 ppm (± se) at high tide.
Increased rate of phosphate supply led to the growth
of two species of photosynthetic alga, O. agardhii
and A. Formosa (Tilman et al, 1982). Tilman et al
(1982) proved that nitrogen and phosphate limitation
was the factor which led to a succession of algal
growth.
Horne et al, (1972) measured dissolved
nutrients in the lake. In Oaks arm, nitrogen fixation
was very low, but much higher in the two basins
where high nitrogen fixation was occurring. This
observation suggests that the possibility of a lasting
nitrogen gas and phosphate gas limitation in Oaks
arm following the peak of the bloom at the end of
August. In contrast, organic dissolved nitrogen
showed no significant variation. Horne et al (1972)
provide a reasonable answer as to why low nitrogen
concentration was found at certain times and only in
non oligotrophic lakes. In oligotrophic lakes, these
conditions of some combined inorganic nitrogen and
sufficient dissolved organic nitrogen may never
occur. In stratified non-oligotrophic lakes, the
condition is normally only provided toward the end
of a spring bloom and during autumn overturn. In
non-stratified, non-oligotrophic lakes, the condition
may occur at irregular intervals throughout the year
were dependent on nitrogen turnover rates. Carbon,
Nitrogen and Phosphorus are the chemical building
blocks for living organism, therefore nitrogen
fixation is a natural process that is needed in order for
all organisms to survive, (Tzortziou, 2007 ) but the
over use of nitrogen gas becomes a toxin that may
also harm marine life. As water was collected and
nitrogen gas and phosphorous gas levels were
calculated with a DR/850 Calorimeter (Hach
Company, CO. U.S.A) from Dana Point Harbor in
Southern California at both low and high tide; Nitrate
ions and Phosphorous gas levels did in fact increase
as sea levels increased. This DR/850 Calorimeter
devise has several settings and packets that contain
compounds that create reactions obtaining accurate
results. The mean of phosphate gas concentration was
0.28 ± 0.02 ppm (± se) (N=3) at low tide and 0.77 ±
0.09 ppm (± se) (N=3) at high tide. Nitrate ion
concentrations were 1.07 ± 0.27 ppm (± se) at low
tide and 1.5 ± 0.1 ppm (± se) at high tide; although
there was no significant difference of nitrate ion
levels between low and high tide. Nitrogen gas that
ends up in the ocean waters by run offs of farmlands
are contributing to the outbreak of Domoic acid (Pan
et al, 1996) ; as the fish eat the polluted plankton, the
toxins become more potent, then marine mammals
consume this contaminated food source, affecting
them tremendously. As a result their bodies can no
longer digest the toxins and their brain’s
hippocampus becomes paralyzed resulting in seizures
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Saddleback Journal of Biology
Spring 2008