EXPLORING PORPHYRA SPECIES FOR USE AS NITROGEN SCRUBBERS IN INTEGRATED AQUACULTURE

Carmona, R.¹, Kraemer G. P.², Zertuche, J. A.³, Chanes, L.⁴, Chopin, T.⁵, Neefus C.^4,6 & Yarish, C.^{1 1}Dept. of Ecol. and Evol. Biol., University of Connecticut, One University Place, Stamford, CT 06901, USA; ²Department of Environmental Sciences, State University of New York, Purchase, NY 10577 USA; ³IIO, Universidad Autonoma de Baja California. Ensenada,B.C., Mexico; ⁴DGETI-CBTis41, Mexico; ⁵CCSA, Dept. of Biol., University of New Brunswick, Saint John, N.B., E2L 4L5, Canada; ⁶Department of Plant Biology, University of New Hampshire, Durham, NH 03824, USA Finfish mariculture along the Northeast US coast continues to develop into a strong industry. At a regional level, mariculture can be a significant contributor to nutrient loading in coastal waters. Since macroalgae are able to concentrate nutrients and grow at high rates, they can be an useful tool for alleviating this problem. In addition, seaweed mariculture is by itself a multi-billion dollar industry, with the red alga Porphyra (nori) valued at over $US 1.8 billion. Local species and strains of Porphyra from the Northeast U.S.A. are being studied to determine their capacity as nutrient scrubbers under different nutrient and temperature conditions. P. purpurea was grown under two N sources (NO3- vs. NH4+). The fastest growth (up to 13% d-1) and greatest N content (ca. 7% DW) were measured in plants grown at 300 µM NH4+. Short-term NH4+ uptake by P. purpurea (strains from Maine and Long Island Sound) and by P. amplissima was not saturated at 150 µM, the highest concentration tested. The P. purpurea isolate from Maine took up NH4+ faster than did the Long Island Sound isolate. NH⁴⁺ uptake by P. amplissima was faster than uptake by either P. purpurea strain. The high growth rates obtained and the ability for N uptake and tissue accumulation make these species suitable for using as a biological nutrient removal system.     

液氮保存曲霉菌种的效果

本文报告了以蒸馏水、10%甘油和5%二甲基亚砜(DMSO)为保护剂,用液氮冻结法保存5种8株曲霉的效果,并检测了这些菌分别产生的亚甲基丁二酸、柠檬酸、蛋白酶和糖化酶的生理活性。这些菌在液氮气相(接近-150℃)中保存180天全部保持着生活能力,它们的培养特征和形态特征保留原来的形状。所测定的液氮保存8株菌种的生理活性,除两株糖化酶活力稍有降低外,其它菌株没有明显的变化。     

液氮冻结法保藏毛霉目菌种的效果

本文报告了用液氮冻结法保藏毛霉目菌种的效果。对14属26种32株进行了液氮保藏试验,其结果慢速冻结孢子成活率高于快速冻结。用10%的甘油、10%的二甲基亚砜和蒸馏水作保护剂制成的孢子悬液,经慢速冻结后储存在液氮罐气态中二年,以甘油作保护剂的孢子成活率为90%,二甲基亚砜的为85%,蒸馏水的为79%。并检测了某些菌株的反丁烯二酸、蛋白酶、α-半乳糖苷酶、脂肪酶、果胶酶、葡萄糖苷酶等生理活性,结果冻结后的活性与冻结前相比,无明显差异。     

EVALUATIONS OF THE AVAILABILITY OF SOURCES OF NITROGEN AND PHOSPHORUS FOR ALGAE1

Techniques are compared for the evaluation of nutrient sources in which the potential nutrients are in contact with algae over their entire culture period versus relatively short-term exposure tests. Different nitrogen and phosphorus compounds were shown to be utilized in darkness as well as in light and were equally available at pH 7 and 9. The availability of relatively insoluble nutrients–iron-phosphorus compounds and teeth for phosphorus, hair for nitrogen iron pyrites for iron, and marble for carbon–indicates that in many cases the equilibrium between soluble and insoluble forms allows algae to compete successfully with insoluble forms for nutrients. Apparently, factors other than mere insolubility prevent algae from obtaining available nitrogen or phosphorus from phosphate rock or lake muds. Live algae or aquatic weeds with adequate or surplus nitrogen or phosphorus were shown to not share their nutrients with nitrogen- or phosphorus-limited algae, whereas the nutrients of killed algae or aquatic weeds were readily used by nutrient-limited algae. The facts–(1) that live algae and aquatic weeds do not share their adequate or surplus nutrients with nutrient-limited algae and (2) that lake muds do not provide readily available nitrogen or phosphorus–indicate that once lake waters are stripped of available nutrients by plant production, further plant production will depend upon nutrients from continuous sources of nutrients, such as wastewater effluents.