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Seasonal Changes in Mycosporine-Like Amino Acid Production Rate with Respect to Natural Phytoplankton Species Composition.

Ha SY, Lee Y, Kim MS, Kumar KS, Shin KH - Mar Drugs (2015)

Bottom Line: The dominance of diatoms indicated that they had a long-term response to UVR.Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure.In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae).

View Article: PubMed Central - PubMed

Affiliation: Division of Polar Ocean Environment, Korea Polar Research Institute (KOPRI), 26 Songdomirae-ro, Yeonsu-gu, Incheon 406-840, Korea. syha@kopri.re.kr.

ABSTRACT
After in situ incubation at the site for a year, phytoplanktons in surface water were exposed to natural light in temperate lakes (every month); thereafter, the net production rate of photoprotective compounds (mycosporine-like amino acids, MAAs) was calculated using (13)C labeled tracer. This is the first report describing seasonal variation in the net production rate of individual MAAs in temperate lakes using a compound-specific stable isotope method. In the mid-latitude region of the Korean Peninsula, UV radiation (UVR) usually peaks from July to August. In Lake Paldang and Lake Cheongpyeong, diatoms dominated among the phytoplankton throughout the year. The relative abundance of Cyanophyceae (Anabaena spiroides) reached over 80% during July in Lake Cheongpyeong. Changes in phytoplankton abundance indicate that the phytoplankton community structure is influenced by seasonal changes in the net production rate and concentration of MAAs. Notably, particulate organic matter (POM) showed a remarkable change based on the UV intensity occurring during that period; this was because of the fact that cyanobacteria that are highly sensitive to UV irradiance dominated the community. POM cultured in Lake Paldang had the greatest shinorine (SH) production rate during October, i.e., 83.83 ± 10.47 fgC·L(-1)·h(-1). The dominance of diatoms indicated that they had a long-term response to UVR. Evaluation of POM cultured in Lake Cheongpyeong revealed that there was an increase in the net MAA production in July (when UVR reached the maximum); a substantial amount of SH, i.e., 17.62 ± 18.34 fgC·L(-1)·h(-1), was recorded during this period. Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure. In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae).

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Transmission of UV-B radiation by Polycarbonate and Quartz bottles.
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marinedrugs-13-06740-f004: Transmission of UV-B radiation by Polycarbonate and Quartz bottles.

Mentions: In order to determine the MAA concentration and net production rate during natural UVR exposure, in situ incubation experiments were conducted at sites in Lake Paldang and Lake Cheongpyeong (Figure 3). Surface water was collected from March to November 2008 on a monthly basis at the sampling stations of Lake Paldang and Lake Cheongpyeong; the water samples were transferred to quartz (HanJin Quartz Co., Seoul, South Korea) and polycarbonate bottles (PC; Nalgene®Labware, Rochester, NY, USA) in duplicate for in situ incubation analysis. Quartz bottles were used for PAR+UV-A+UV-B (PAB) radiation treatment while PC bottles (which block the transmission of UV-B radiation) were used for PAR+UV-A (PA) radiation treatment (control). The transmission spectra of quartz and PC bottles (Figure 4) were measured by spectrophotometer (Cary® 50, Agilent, Santa Clara, CA, USA). An in situ culture experiment using 13C tracer was performed according to Hama [24]. (13C)-Labeled sodium bicarbonate, i.e., NaH13CO3 (99%), which was added as a tracer, increased up to 15% of the 13C in the total dissolved inorganic carbon pool. To observe the effects of UVR, the incubation bottles were then immersed at the surface (within 1 m) of the seawater at the in situ sampling stations of Lake Paldang and Lake Cheongpyeong; here, the bottles remained incubated for 4 h at mid-daylight (from 10 am to 2 pm). After exposure, incubated samples were filtered using pre-burned (450 °C, 4 h) GF/F 47-mm filter paper. They were then transported to the laboratory using a liquid nitrogen container; the filtered samples were stored at −80 °C until they were analyzed.


Seasonal Changes in Mycosporine-Like Amino Acid Production Rate with Respect to Natural Phytoplankton Species Composition.

Ha SY, Lee Y, Kim MS, Kumar KS, Shin KH - Mar Drugs (2015)

Transmission of UV-B radiation by Polycarbonate and Quartz bottles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663551&req=5

marinedrugs-13-06740-f004: Transmission of UV-B radiation by Polycarbonate and Quartz bottles.
Mentions: In order to determine the MAA concentration and net production rate during natural UVR exposure, in situ incubation experiments were conducted at sites in Lake Paldang and Lake Cheongpyeong (Figure 3). Surface water was collected from March to November 2008 on a monthly basis at the sampling stations of Lake Paldang and Lake Cheongpyeong; the water samples were transferred to quartz (HanJin Quartz Co., Seoul, South Korea) and polycarbonate bottles (PC; Nalgene®Labware, Rochester, NY, USA) in duplicate for in situ incubation analysis. Quartz bottles were used for PAR+UV-A+UV-B (PAB) radiation treatment while PC bottles (which block the transmission of UV-B radiation) were used for PAR+UV-A (PA) radiation treatment (control). The transmission spectra of quartz and PC bottles (Figure 4) were measured by spectrophotometer (Cary® 50, Agilent, Santa Clara, CA, USA). An in situ culture experiment using 13C tracer was performed according to Hama [24]. (13C)-Labeled sodium bicarbonate, i.e., NaH13CO3 (99%), which was added as a tracer, increased up to 15% of the 13C in the total dissolved inorganic carbon pool. To observe the effects of UVR, the incubation bottles were then immersed at the surface (within 1 m) of the seawater at the in situ sampling stations of Lake Paldang and Lake Cheongpyeong; here, the bottles remained incubated for 4 h at mid-daylight (from 10 am to 2 pm). After exposure, incubated samples were filtered using pre-burned (450 °C, 4 h) GF/F 47-mm filter paper. They were then transported to the laboratory using a liquid nitrogen container; the filtered samples were stored at −80 °C until they were analyzed.

Bottom Line: The dominance of diatoms indicated that they had a long-term response to UVR.Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure.In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae).

View Article: PubMed Central - PubMed

Affiliation: Division of Polar Ocean Environment, Korea Polar Research Institute (KOPRI), 26 Songdomirae-ro, Yeonsu-gu, Incheon 406-840, Korea. syha@kopri.re.kr.

ABSTRACT
After in situ incubation at the site for a year, phytoplanktons in surface water were exposed to natural light in temperate lakes (every month); thereafter, the net production rate of photoprotective compounds (mycosporine-like amino acids, MAAs) was calculated using (13)C labeled tracer. This is the first report describing seasonal variation in the net production rate of individual MAAs in temperate lakes using a compound-specific stable isotope method. In the mid-latitude region of the Korean Peninsula, UV radiation (UVR) usually peaks from July to August. In Lake Paldang and Lake Cheongpyeong, diatoms dominated among the phytoplankton throughout the year. The relative abundance of Cyanophyceae (Anabaena spiroides) reached over 80% during July in Lake Cheongpyeong. Changes in phytoplankton abundance indicate that the phytoplankton community structure is influenced by seasonal changes in the net production rate and concentration of MAAs. Notably, particulate organic matter (POM) showed a remarkable change based on the UV intensity occurring during that period; this was because of the fact that cyanobacteria that are highly sensitive to UV irradiance dominated the community. POM cultured in Lake Paldang had the greatest shinorine (SH) production rate during October, i.e., 83.83 ± 10.47 fgC·L(-1)·h(-1). The dominance of diatoms indicated that they had a long-term response to UVR. Evaluation of POM cultured in Lake Cheongpyeong revealed that there was an increase in the net MAA production in July (when UVR reached the maximum); a substantial amount of SH, i.e., 17.62 ± 18.34 fgC·L(-1)·h(-1), was recorded during this period. Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure. In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae).

Show MeSH
Related in: MedlinePlus