Experimental Study On The Effects Of Light And The Concentration Of Iron On Phytoplankton Growth Of Small Xingkai Lake

In order to study the light intensity, concentration of iron ion and the relationship between the phytoplankton abundance, so it is concluded that the most suitable light intensity and iron ion concentration of phytoplankton growth. This article choosed the water samples of small Xingkai lake respectively as experimental material on May, July and September. Water sample laboratory culture experiment was carried out through the change of phytoplankton abundance.Experimental results show that for small Xingkai lake water samples of respectively in May, July and September for 12 days of training, identified seven phytoplankton 87 species and varieties. The chlorophyta species up to 41, accounts for about 47%; Bacillariophyta times, 26, accounting for 30%; 10 kinds of cyanophyta, accounts for about 12%; Five chrysophyte door, accounts for about 6%; Hidden algae door and euglenophyta were 2 species, accounts for about 2%; 1 pyrrhophyta, accounts for about 1%. Small Xingkai lake phytoplankton abundance in every month and light conditions, and the differences between the iron concentration. Abundance fluctuations in 9.6 X 104 ind/L-2832×2832 ind/L, for the highest in May 12000 Lx,5μmol/L, under the condition of 2832 X 104 ind/L; Min. In September 2000Lx,9μmol/L 为9.6×104 ind/LUnder the condition of different illuminations, phytoplankton abundance with iron concentration changed and different. In different months, under the condition of same illumination, phytoplankton abundance changed with iron concentration. Phytoplankton species composition is different, different demand for light and iron concentration, so from some of the dominant species increased or reduced sharply to show that iron concentration changed can affect the change of the whole group of the phytoplankton abundance. Algae that individual optimum illumination and iron concentration, July 1000Lx illumination,7μmol/L iron concentration condition, curly fishy algae (Anabaena circinalis) have significantly increased;7 September 1000Lx illumination,7μmol/L iron concentration condition, cyanophyta tiny flat crack algae (Merismopedia tenuissima) growed vigorous; September 2000Lx light 7μmol/L iron concentration, short-term brittle pole algae (Fragilaria brevistriata) and sun in September 2000Lx 5μmol/L iron concentration in the solid microcystin algae (Microcystis) do best. In September 12000Lx illumination 7μmol/L iron concentration of nitrogen fixation fishy algae (Anabaena azotica) growth.Algae growth along with the increase of light intensity, but the light intensity is too high algae growth will be suppressed, or the increase of light intensity and not for all function to promote the growth of algae. Light affect the phytoplankton community structure, demand for light intensity is different, different algae in strong light conditions, cyanophyta, bacillariophyta of micro and small phytoplankton growth is the fastest, and type of phytoplankton growth is not obvious.Under the condition of low illumination, phytoplankton abundance by Fe uptake was not change regularly, phytoplankton uptake of Fe, and phytoplankton abundance is not increased. This suggests that under the condition of low illumination, pigment cells increased because of the demand for iron capture light to reaction centers of photosynthesis ratio increases, and the intracellular chlorophyll content increased with iron reaction center and the rise of the electron transport chain.Under the condition of light intensity of 8000Lx, phytoplankton abundance were positively correlated with Fe uptake. Are increased with the increase of Fe uptake increased and total abundance than 1000Lx and 4000Lx under the light intensity is much higher. That 8000Lx illumination conditions is the most suitable for algae growth. Thus, the increase of light intensity, is not only beneficial to the growth of algae, but also accelerated the biological availability Fe was consumed by algal cells. Under the condition of light intensity of 12000Lx, phytoplankton uptake of Fe is less than 8000Lx and 4000Lx, and phytoplankton abundance is higher, this shows that the light intensity of algae growth restriction is significantly higher than medium, Fe restrictions on algae growth.