Won Chan Lee

Algal photosynthetic responses to toxic metals and herbicides assessed by chlorophyll a fluorescence.

Chlorophyll a fluorescence is established as a rapid, non-intrusive technique to monitor photosynthetic performance of plants and algae, as well as to analyze their protective responses. Apart from its utility in determining the physiological status of photosynthesizers in the natural environment, chlorophyll a fluorescence-based methods are applied in ecophysiological and toxicological studies to examine the effect of environmental changes and pollutants on plants and algae (microalgae and seaweeds). Pollutants or environmental changes cause alteration of the photosynthetic capacity which could be evaluated by fluorescence kinetics. Hence, evaluating key fluorescence parameters and assessing photosynthetic performances would provide an insight regarding the probable causes of changes in photosynthetic performances. This technique quintessentially provides non-invasive determination of changes in the photosynthetic apparatus prior to the appearance of visible damage. It is reliable, economically feasible, time-saving, highly sensitive, versatile, accurate, non-invasive and portable; thereby comprising an excellent alternative for detecting pollution. The present review demonstrates the applicability of chlorophyll a fluorescence in determining photochemical responses of algae exposed to environmental toxicants (such as toxic metals and herbicides).

Physiological disturbance of the Manila clam, Ruditapes philippinarum, by altered environmental conditions in a tidal flat on the west coast of Korea

To examine the influence of habitat alteration by tideflat reclamation on the physiological ecology of Ruditapes philippinarum, seasonal variations in its condition, gross biochemical composition, and reproductive cycle were compared for a yearly cycle between a reclaimed flat (Gomsohang, GS) and a natural flat (Hajun, HJ) in Gomso Bay, Korea. Concentrations of chlorophyll a and seston (as well as its energy value as food available to the clam) were consistently higher at HJ than at GS. Condition, dry tissue weight, and energy reserves (proteins and carbohydrates) of the clams were much higher at HJ than at GS during spring-summer, when fast growth and gametogenic development occur. Furthermore, their spring gametogenic development and spawning were advanced at HJ compared with GS. Our results suggest that the Manila clam encounters nutritionally stressful environmental conditions in altered habitats after tideflat reclamation that lead to lowered nutrient accumulation and a changing reproductive cycle.

Infant exposure to polybrominated diphenyl ethers (PBDEs) via consumption of homemade baby food in Korea.

Limited data are available on the residue levels of polybrominated diphenyl ethers (PBDEs) in baby food. In this study, 24 PBDE congeners were determined in 147 homemade baby food samples collected from 97 households for 6-, 9-, 12-, 15-, and from 24 to 27-month-old infant groups during the period of 2012-2013. The concentrations of total PBDEs (ΣPBDE) ranged from 24.5 to 6000 (mean: 263) pg/g fresh weight, higher than those found in commercial formulae from the United States. The predominant congeners were BDEs 209 and 47, accounting for 92% of the ΣPBDE concentrations, reflected by high deca-BDE consumption in Korea. The residue levels and detection rates of BDE 47 in the baby food samples showed a gradual increasing trend with an increase in infant ages, due to changes in the food ingredients from hypoallergenic to greasy. The daily intakes of BDEs 47 and 209 via baby food consumption ranged from 0.04 to 0.58, 0.80 to 20.3, and 1.06 to 22.3 ng/kg body weight/day for 6-, 9-, 12-, 15-, and 24-27-month-old infant groups, respectively; these intakes were lower than the oral reference doses proposed by the US EPA. Together with three exposure sources, baby food, breast milk and dust ingestion for 6-month-old infants, the daily intake of ΣPBDE was 25.5 ng/kg body weight/day, which was similar to the intake via baby food consumption only for over 24-month-old infants in our study. This indicates that baby food is an important exposure pathway of PBDEs for over 24-month-old infants. This is the first study regarding the occurrence and exposure assessment of PBDEs via homemade baby food.

Trophic structure in a pilot system for the integrated multi-trophic aquaculture off the east coast of Korean peninsula as determined by stable isotopes

To assess the potential for nutritional exploitation of caged-fish-derived waste through the use of extractive co-cultured species in a pilot system for an integrated multi-trophic aquaculture (IMTA), we compared their C and N stable isotope ratios with those of uncultured macroinvertebrates in and around the system. Black rockfish were co-cultured with sea cucumber, oyster, and two macroalgae as extractive species. Isotope signatures of the co-cultured sea cucumber at the IMTA site differed from those at the control site, indicating their assimilation of aquaculture wastes. In contrast, δ(13)C and δ(15)N of individual taxa of the cultured oyster and uncultured invertebrates were consistent between sites, suggesting a minor contribution of the aquaculture waste to benthic and pelagic food chains in and around the IMTA system. These results provide evidence of the suitability of using sea cucumber as an extractive species to reduce the impact of a monoculture system on the ambient environment.

Dissolved Nutrient Balance and Net Ecosystem Metabolism Using a Simple Box Model in Gamak Bay, Korea

The budgets of fresh water, salt and nutrients were estimated in order to clarify the characteristics of material cycle in the Gamak Bay in 2006 with Simple Box budget Model. Outflow volume of freshwater into system was approximately -174.2~72.5×10 3 m 3 /day. Inflow masses of DIP and DIN were approximately 397.0~1158 mole/day and 1750~8328 mole/day, respectively. The Source or sink of DIP was under the control of the variation of fresh water budget in the system. the mass balance and NEM was largely determined by flushing time of material.

Physiological processes and gross energy budget of the submerged longline-cultured Pacific oyster Crassostrea gigas in a temperate bay of Korea

Physiological processes and gross energy budget of the longline-cultured Pacific oyster Crassostrea gigas were investigated in Geoje–Hansan Bay, Korea during two entire culturing periods. Based on physiological measurements of food consumption, feces production, ammonium excretion, and respiration from July 2008 to February 2009 and from July 2013 to February 2014, scope for growth appeared to be positive during most of the culturing period, except for one period with extremely high temperatures (up to 25°C). Estimates of physiological energy production matched well with tissue energy increment measured by gross biochemical composition during the culturing period, suggesting that the oysters might adjust their physiological performance to relatively low concentrations of suspended particulate matter in the bay to optimize energy acquisition. Such an adaptive adjustment includes an increased absorption of energy and a reduced loss of metabolic and excretory energy, resulting in positive production under high culturing density. Using physiological measurements, we further assessed the feedback effects of the longline aquaculture of oysters on the bay system. Ecological efficiency, estimated by a series of energetic efficiencies at the whole bay level, was low compared with Lindeman’s law of trophic efficiency. Biodeposition and ammonia excretion rates in this study were relatively low compared with other intertidal plastic bag cultures. These results indicate that the cultured oysters might have only minor effects on benthic and pelagic environments of the bay. Overall, our results suggest that the adaptive physiological performance of oysters and consequently weak feedback effects on ambient habitats should facilitate sustainable longline aquaculture in the bay for a prolonged period without severe habitat deterioration.

Ecological Characteristics of the New Recorded Seahorse (Hippocampus haema) in Geoje-Hansan Bay, Korea

ABSTRACT Kim, M.J.; Kim, H.C.; Lee, W.C.; Park, J.M.; Kwak, S.N.; Oh, Y.; Kang, M.G., and Lee, S.H., 2018. Ecological characteristics of the new recorded seahorse in Geoje-Hansan Bay, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 351–355. Coconut Creek (Florida), ISSN 0749-0208. A basic ecological research of the seahorse populations has not been done to date even though the population is declining due to overfishing, by-catching and heavy human activities. Recently reported seahorse (Hippocampus haema) samples were monthly collected in Geoje–Hansan bay for a year from August 2015 to August 2016. Standard length (SL), weight (Wt), coronet height (CH), trunk length (TrL), and tail length (TaL) of each individual were measured for identifying characteristics of H. haema. The ranges of temperature and salinity were 8.2–26.0 °C and 29.3–34.1 ‰, respectively. Mean SL and Wt for all the groups were 55.26 ± 16.11 mm and 0.32 ± 0.25 g, respectively. There were significant differences in the relative ratios of each length factor (TrL, TaL and CH) and condition factors (CFs) according to gender or breeding period (ANOVA, p < 0.01). Since pregnant males constituted nearly 40 % (18 individuals) in May and juvenile seahorses were first observed in June, 2016, the recruitment of this species appears to begin in June. Based on our one-year field observation, the duration of the breeding season of the H. haema in Geoje-Hansan bay can be estimated for approximately 7 months long which is similar to other seahorse species (generally 4 to 10 months) inhabiting similar latitudes. The results from this study provide important information for a sustainable management and conservation of the new recorded seahorse species.

The Growth of Mugil cephalus, Patinopecten yessoensis and Saccharina japonica in the IMTA System

In this study, we investigated the growth of striped mullet (Mugil cephalus), Yesso scallop (Patinopecten yessoensis) and kelp (Saccharina japonica) farmed under the IMTA (integrated multi-trophic aquaculture) system developed by national institute of fisheries science (NIFS). The farmed striped mullets grew from an initial length and weight of 152.5±12.1 and 41.6±7.8 g in October 2013 to 154.2±5.6 and 47.5±8.6 g in November, 160.2±8.7 and 55.9±9.1 g in December and 168.4±9.6 and 58.4±8.7 g in January. The fish continued to grow and reached 190.2±9.4 in length and 87.5±8.9 g in weight in April and 256.4±9.7 and 156.7±6.7 g in October 2014. The daily growth rate (DGR) for total fish length was 0.015 0.1 /day during the periods of fast growth and attained 0.038 0.1 /day during February March. The kelp grew from an initial blade length and wet weight of 1.19±0.2 and 0.0028±0.0012 g in January 2014 to 3.3±0.8 and 2.5±0.9 g in February and 126.5±11.6 and 107.4±22.6 g in March, after which, erosion occurred and slowed the growth. The DGRs for kelp length ranged 0.03 1.9 /day in January 2014 and increased to 0.88 1.9 /day during March April. Increasing water temperatures beginning in April lowered the DGR to 0.03 /day. Yesso scallops grew from an initial shell length, shell height and wet weight of 11.83±0.6 , 12.68±0.7 and in September 2013 to 19.9±2.5 , 20.8±2.6 and 0.9±0.04 g in November 2013. They continued to grow to 45.91±0.71 in shell length, 42.55±0.8 in shell height and 12.7±1.3 g in wet weight by May 2014 and 60.2±2.51 , 554.6±2.61 and 24±2.70 g by October 2014. The DGRs for shell length of Yesso scallop ranged from 0.02 to 0.256 /day with higher values of 0.256 0.27 /day during November December 2013 and March April 2014.