Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
Bioinvasion events causing serious environmental damage have been a concern with the mariculture of Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, suggesting the importance of studying the biological aspects of drifting specimens of K.... more
Bioinvasion events causing serious environmental
damage have been a concern with the mariculture of
Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, suggesting
the importance of studying the biological aspects of drifting
specimens of K. alvarezii for monitoring programs. The present
study aims to evaluate the tolerance and growth of drifting
color variants of K. alvarezii under different temperatures and
salinities to determine their physiological capacity for growing
outside cultivation rafts. Drifting color variants were collected
in Paraíba State, Brazil, in November 2011(dry month)
and August 2012 (rainy month), and cultivated in the laboratory
under different temperatures (20, 24, 28, and 32 °C) and
salinities (15, 25, 35, 45, and 55 psu). Growth rates as
well as pigment and protein contents were determined.
Results showed that drifting specimens collected in the
dry month showed higher tolerance to variation in temperature
(20 to 28 °C) and salinity (25 to 35 psu) than
drifting specimens collected in the rainy month. Higher
growth rates occurred in samples cultured at 20 and 24 °C
(2.8–3 % day−1) and 25 to 35 psu (3.4–3.5 % day−1), suggesting
temperature and salinity optima. Higher phycobiliprotein
levels were observed in the red and brown variants under
hypersaline conditions (45 and 55 psu). Higher chlorophyll
a contents were associated with samples cultivated at 20–
24 °C and 24–35 psu. Based on the results of the present
study, drifting specimens collected in dry month are more
tolerant to temperature and salinity variations, suggesting that
the drifting K. alvarezii should be monitored especially during
this period to prevent its establishment outside the cultivation
rafts and dispersion along the northeastern coast of Brazil.
Keywords Kappaphycus alvarezii . Drifting color variants .
Growth . Salinity . Temperature . Tolerance . Tropical waters
damage have been a concern with the mariculture of
Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, suggesting
the importance of studying the biological aspects of drifting
specimens of K. alvarezii for monitoring programs. The present
study aims to evaluate the tolerance and growth of drifting
color variants of K. alvarezii under different temperatures and
salinities to determine their physiological capacity for growing
outside cultivation rafts. Drifting color variants were collected
in Paraíba State, Brazil, in November 2011(dry month)
and August 2012 (rainy month), and cultivated in the laboratory
under different temperatures (20, 24, 28, and 32 °C) and
salinities (15, 25, 35, 45, and 55 psu). Growth rates as
well as pigment and protein contents were determined.
Results showed that drifting specimens collected in the
dry month showed higher tolerance to variation in temperature
(20 to 28 °C) and salinity (25 to 35 psu) than
drifting specimens collected in the rainy month. Higher
growth rates occurred in samples cultured at 20 and 24 °C
(2.8–3 % day−1) and 25 to 35 psu (3.4–3.5 % day−1), suggesting
temperature and salinity optima. Higher phycobiliprotein
levels were observed in the red and brown variants under
hypersaline conditions (45 and 55 psu). Higher chlorophyll
a contents were associated with samples cultivated at 20–
24 °C and 24–35 psu. Based on the results of the present
study, drifting specimens collected in dry month are more
tolerant to temperature and salinity variations, suggesting that
the drifting K. alvarezii should be monitored especially during
this period to prevent its establishment outside the cultivation
rafts and dispersion along the northeastern coast of Brazil.
Keywords Kappaphycus alvarezii . Drifting color variants .
Growth . Salinity . Temperature . Tolerance . Tropical waters
Research Interests:
The selection of seaweed species for their use as biofilters should be based on the knowledge of their nutrient requirements and tolerance to wide variations of nutrient concentrations. Therefore, tolerance and the physiological... more
The selection of seaweed species for their use as
biofilters should be based on the knowledge of their nutrient
requirements and tolerance to wide variations of nutrient concentrations.
Therefore, tolerance and the physiological capabilities
of Hypnea cervicornis J. Agardh (Gigartinales, Rhodophyta) to growth under nitrate, ammonium, and phosphate variations and to assimilate them into soluble proteins and photosynthetic pigments were evaluated in laboratory conditions. Treatments were composed of sterilized seawater
enriched with 25% von Stosch solution (without nitrogen and
phosphorus), and nitrate or ammonium and phosphate were
added in combination of 100:1 and 10:1 nitrogen/phosphorus
(N/P). Nitrate concentrations varied from 0 to 500 μM, and
ammonium concentrations varied from 0 to 50 μM. Growth
rates of H. cervicornis increased linearly with addition of
ammonium, but with nitrate addition, growth varied following
a saturation kinetic, and the highest growth rate (14.45 % d−1)
was observed in 200 μM of N/P ratio of 10:1. An excess of
nutrients was accumulated as proteins and phycobiliproteins
(mainly as allophycocyanin and phycoerythrin) at higher
phosphate availability (N/P ratio of 10:1), and H. cervicornis
tolerated the highest ammonium and nitrate concentrations
(50 and 500 μM, respectively). These physiological responses
suggest that this species could be used as biofilter for nutrient
removal in eutrophicated seawater and could be cultivated in
integrated multitrophic aquaculture systems.
Keywords Ammonium . Hypnea . Nitrate. Nitrogen storage . Pigments . Phosphate . Proteins
biofilters should be based on the knowledge of their nutrient
requirements and tolerance to wide variations of nutrient concentrations.
Therefore, tolerance and the physiological capabilities
of Hypnea cervicornis J. Agardh (Gigartinales, Rhodophyta) to growth under nitrate, ammonium, and phosphate variations and to assimilate them into soluble proteins and photosynthetic pigments were evaluated in laboratory conditions. Treatments were composed of sterilized seawater
enriched with 25% von Stosch solution (without nitrogen and
phosphorus), and nitrate or ammonium and phosphate were
added in combination of 100:1 and 10:1 nitrogen/phosphorus
(N/P). Nitrate concentrations varied from 0 to 500 μM, and
ammonium concentrations varied from 0 to 50 μM. Growth
rates of H. cervicornis increased linearly with addition of
ammonium, but with nitrate addition, growth varied following
a saturation kinetic, and the highest growth rate (14.45 % d−1)
was observed in 200 μM of N/P ratio of 10:1. An excess of
nutrients was accumulated as proteins and phycobiliproteins
(mainly as allophycocyanin and phycoerythrin) at higher
phosphate availability (N/P ratio of 10:1), and H. cervicornis
tolerated the highest ammonium and nitrate concentrations
(50 and 500 μM, respectively). These physiological responses
suggest that this species could be used as biofilter for nutrient
removal in eutrophicated seawater and could be cultivated in
integrated multitrophic aquaculture systems.
Keywords Ammonium . Hypnea . Nitrate. Nitrogen storage . Pigments . Phosphate . Proteins