@article {KNZ00865,
	title = {Misuse of inorganic N and soluble reactive P concentrations to indicate nutrient status of surface waters},
	journal = {Journal of the North American Benthological Society},
	volume = {22},
	year = {2003},
	pages = {171 -181},
	abstract = {Dissolved inorganic N (DIN) and soluble reactive P (SRP) have been used by some to indicate the trophic status of waters, and concentration ratios (DIN:SRP) to indicate nutrient deficiency. The utility of such measurements should be questioned, particularly based on well-known problems associated with determination of the concentration of SRP, which is commonly assumed to represent PO43-. Another potential problem with using inorganic nutrient pools to represent trophic state and nutrient availability ratios arises because concentration values are in units of mass per unit volume, and cannot be used with certainty to estimate supply (i.e., turnover rate of the nutrient pool, expressed either in mass per unit volume per unit time or simply as per unit time) to organisms without information on uptake and remineralization. Two data sets with lotic water-column nutrient values were explored, a large, continental-scale data set with analyses and collections done by many laboratories, and a more limited data set collected and analyzed by the same laboratory. In concert, the data sets indicated that at high total N (TN) (i.e., >5 mg/L) and total P (TP) (i.e., >2 mg/L) concentrations, >60\% of the nutrient is usually made up of dissolved inorganic forms, but at low levels the ratio of dissolved inorganic to total nutrients is highly variable. Last, DIN:SRP is a weak surrogate for TN:TP and thus should be used with caution to indicate nutrient limitation.},
	keywords = {LTER-KNZ, ammonium, dissolved reactive phosphorus, inorganic nutrients, Nitrate, nutrient limitation, phosphate, water-quality monitoring},
	doi = {10.2307/1467990},
	author = {W. K. Dodds}
}
@article {KNZ00888,
	title = {The role of periphyton in phosphorus retention in shallow freshwater aquatic systems},
	journal = {Journal of Phycology},
	volume = {39},
	year = {2003},
	pages = {830 -849},
	abstract = {<p>Eutrophication caused by phosphorus (P) leads to water quality problems in aquatic systems, particularly freshwaters, worldwide. Processing of nutrients in shallow habitats removes P from water naturally and periphyton influences P removal from the water column in flowing waters and wetlands. Periphyton plays several roles in removing P from the water column, including P uptake and deposition, filtering particulate P from the water, and attenuating flow, which decreases advective transport of particulate and dissolved P from sediments. Furthermore, periphyton photosynthesis locally increases pH by up to 1 unit, which can lead to increased precipitation of calcium phosphate, concurrent deposition of carbonate-phosphate complexes, and long-term burial of P. Actively photosynthesizing periphyton can cause super-saturated O2 concentrations near the sediment surface encouraging deposition of metal phosphates. However, anoxia associated with periphyton respiration at night may offset this effect. Linking the small-scale functional role of periphyton to ecosystem-level P retention will require more detailed studies in a variety of ecosystems or large mesocosms. A case study from the Everglades illustrates the importance of considering the role of periphyton in P removal from wetlands. In general, periphyton tends to increase P retention and deposition. In pilot-scale constructed periphyton-dominated wetlands in South Florida, about half of the inflowing total P was removed.</p>},
	keywords = {LTER-KNZ, eutrophication, microalgae, microphytobenthos, periphyton, phosphate, Phosphorus, tertiary treatment, water quality},
	doi = {10.1046/j.1529-8817.2003.02081.x},
	author = {W. K. Dodds}
}
