Indications from photosynthetic components that iron is a limiting nutrient in primary producers on coral reefs

Response of the marine diatom Thalassiosira weissflogii to iron stress1

“…Such a result, which should be demonstrated directly, would be consistent with the apparent increase in short term uptake rate of manganese in high iron medium in response to an effective manganese limitation (Table 3). In view of the known substitution of flavodoxin for ferredoxin in some cyanobacteria (Entsch et al 1983), it may well be that iron and manganese exhibit a complex set of long term synergistic and short term antagonistic interactions in phytoplankton.…”

“…In oxygenated seawater the low solubility of ferric hydroxide has been hypothesized to limit the biological availability of iron and algal growth (Menzel and Ryther 1960). Indeed, there is recent evidence of iron limitation of marine photosynthetic organisms (Entsch et al 1983;Subba Rao and Yeats 1984).…”

“…For example, in bacteria, superoxide dismutase may contain either iron or manganese depending on their concentrations (Meier et al 1982). In cyanobacteria the synthesis of flavodoxin, a noniron-containing electron carrier, is favored over ferredoxin, a Fe-S protein, in response to iron stress (Entsch et al 1983).…”

Physiological and behavioral diagnostics of nitrogen limitation for the toxic dinoflagellate Alexandrium fundyense

“…For unialgal cultures, C:P or C:N ratios are useful parameters to distinguish between nitrogen and phosphorous limitation (Sakshaug and Holm-Hansen 1977), but these do not always provide a clear answer in field conditions due to interspecific variation and contamination from detritus. Another approach has been to identify physiological diagnostics or indicators, such as a specific protein that increases or decreases during a specific nutrient stress (i.e., nitrogen, phosphorous or iron) (Entsch et al 1983;LaRoche et al 1993;Erdner et al 1999). Diagnostics, such as glutamine:glutamate (GLN/GLU) (Flynn et al 1989; and ferredoximflavodoxin (Fd index) (Erdner et al 1999), have been related to specific limitations or stresses (nitrogen and iron) in laboratory cultures and in some cases have been used to monitor the natural environment (LaRoche et al 1996;Erdner and Anderson 1999).…”

Effects of solar ultraviolet radiation on biogeochemical dynamics in aquatic environments : report of a workshop, Marine Biological Laboratory, Woods Hole, Massachusetts, October 23-26, 1989

“…Indeed, Anderson and Morel (1983), Finden et al(1984), Sunda et al(1983) and Sunda (1988) note that iron or manganese may limit algal productivity in some situations and speculate that in such cases, enhancement of limiting nutrient supply through reduction processes may significantly alter algal growth rate, primary productivity, and species distribution. Field evidence that iron or manganese are limiting nutrients in some situations has been provided by Brand et al(1983), Entsch et aL. (1983), , .…”