Effect of nutrient inputs on growth, chlorophyll, and tissue nutrient concentration of Ulva reticulata from a tropical habitat

Abstract

"Green tides" caused by overgrowth of Ulva species are an increasing problem in tropical areas. The effect of dissolved nutrients on uptake rates, growth, chlorophyll, and tissue nutrient concentration of Ulva reticulata was examined in laboratory experiments lasting up to 7 d. Sterile seawater was enriched with nitrate, ammonium, phosphate, ammonium + phosphate and nitrate + phosphate. U. reticulata expressed luxury uptake of both nitrogen (N) and phosphorus (P). The maximum N-uptake rate was found when ammonium was added alone. The maximum relative growth rate was about 15.1% per day but this was in the nitrate-fed algae not the ammonia-fed algae. N-enrichment resulted in an increase in chlorophyll concentration on day 4 and a decrease on day 7, probably as a result of cell division. P-enrichment had no significant effect on chlorophyll concentration. Treatments with added N, P or N+P showed significant increase in tissue N and P content on day 4. On day 7, N content in macroalgal tissue decreased while P content continued to increase. U. reticulata responded most strongly to added N; responses to P were much lower than for added N and there was little or no evidence for an additive effect of N+P. The N:P ratio of U. reticulata of control material suggested that N was the most limiting nutrient at the collection site (Paklok, Phuket, Thailand).

Timing of disturbance, top‐down, and bottom‐up driving on early algal succession patterns in a tropical intertidal community

“…When nutrient enriched, Ulva , an opportunistic alga that has a high uptake rate, can take up large amounts of nutrient, particularly nitrogen (Buapet et al . ). This resulted in a fast growth and an increase of biomass.…”

“…This result suggested that nutrient availability can facilitate the abundance and growth of early successional species, especially turf and filamentous algae. When nutrient enriched, Ulva, an opportunistic alga that has a high uptake rate, can take up large amounts of nutrient, particularly nitrogen (Buapet et al 2008). This resulted in a fast growth and an increase of biomass.…”

Experimental Validation of a Performance Model of a Biofiltration System

“…Three treatments were made: (1) 20: Two-liter CSTR (continuous stirred-tank reactor) with 12rpm stirrer speed was contained with 0.90 gram dry-weight algal biomass (or an algal biomass concentration of 0.45 gram dry-weight per liter). The reactor was fed with unpolluted seawater enriched with ammonium and phosphate at varying concentrations from 10 to 100 µM ammonium and 1 to 10 µM phosphate [3]. The estimated volumetric flow rate of each ammonium and phosphate concentrations was applied.…”

“…Influent and effluent concentrations monitoring were done until a steady-state condition was achieved which is expected to occur within five days. The initial and final algal biomass concentration was determined in each experimental run [3,6]. Light intensity was monitored once in every run.…”

Modeling sources of nutrients in rivers draining into the Bay of Bengal—a scenario analysis

“…Hypoxia and algal blooms have been observed along the coastlines of the BOB LME (Buapet et al 2008;Das et al 2004; Lee and Bong 2006;Meybeck and Helmer 1989;Periyanayagi et al 2007). …”