Light limitations

The two limitations of optical interferometry, the one-quarter wavelength of light limit and the low resolution, have been addressed by using a combination of a fixedthickness spacer layer and spectral analysis of the reflected beam. The first of these overcomes the minimum film thickness that can normally be measured and the second addresses the limited resolution of conventional chromatic interferometry. 

A. A. Tsygankov, T. Laurinavichene, I. Gogotov, Y. Asada, J. Miyake (1996) Switching over from light limitation to ammonium limitation of chemostat cultures of Rhodobacter capsulatus grown in different types of photobioreactors. J. Marine Biotechnol., 4 43-46... 

The continental shelves cover most of the seafloor in the Arctic Ocean, making this the shallowest ocean. Thus, most of the sediments are neritic. Because of light limitation, primary production is inhibited, so river runoff and ice rafting supply most of the particles to this ocean. As a result, lithogenous and glacial marine sediments are most common. 

Another type of seasonally driven export event is associated with larger diatoms (>50pm) that grow vmder nutrient- and light-limited conditions at the base of the euphotic zone. These diatoms seem to imdergo a mass settling event, called a fall dump, in response to destratification of the summer thermocline due to seasonal cooling and early winter storms. These diatoms sink rapidly and are relatively well preserved in the sediments. 

At mid-latitudes (Westerlies domain), seasonal changes in light availability, mixed layer depth, and temperature support two plankton blooms, one in the spring and a lesser one in the fall (Figure 24.10). In the winter, phytoplankton growth is light limited. (The carbon fixation reaction is also slower at lower temperatures.) Thus as heterotrophic microbes remineralize detrital POM, DIN concentrations rise. 

Despite generally high nutrient concentrations in rivers as compared to lakes, primary production in these systems appears to be in the same range as that of lakes due to the strong light limitation in these systems (Cole and Cloern, 1984 Roos and Pieterse, 1992). Annual production varies between 10 and 500 g C m 2yr 1 and averages about 100 g C m 2 yr-1 (Capblancq and Dauta, 1978 Bonnetto, 1983 Bonnetto et al., 1981 Saha et al., 1985 Lewis, 1988 Cole et al., 1989, 1992 Webster and Meyer, 1997). 

Mitchell BG, Brody EA (1991) Light limitation of phytoplankton biomass and macronutrient utilization in the Southern Ocean. Limnol Oceanogr 36 1662-1677 Mohanty N, Gilmore AM, Yamamoto HY (1995) Mechanism of non-photochemical chlorophyll fluorescence quenching. II. Resolution of rapidly reversible absorbance changes at 530 nm and fluorescence quenching by the effects of antimycin, dibucaine and... 

Moisan TA, Mitchell BG (1999) Photopysiological acclimation of Phaeocystis antarctica Karsten under light limitation. Limnol Oceanogr 44(2) 247-288... 

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