DSpace Collection:

Potential Applications of HyspIRI for the Observation of Sea-Margin Processes

2019-01-01T00:00:00Z

Title: Potential Applications of HyspIRI for the Observation of Sea-Margin Processes Authors: Jo, Young-Heon; Kim, Hyun-cheol; Hu, Chuanmin; Klemas, Victor V.; Turpie, Kevin R. Abstract: The Hyperspectral Infrared Imager (HyspIRI) mission will observe the effects of future environmental changes upon the world's ecosystems. Among other applications, this paper reviews three different sea-margin processes that can be monitored by the HyspIRI spectrometer, i.e. groundwater and surface-water discharge, meltwater-pond formation, and shoreline delineation. Groundwater and surface-water discharge to coastal regions affects local ecological conditions through changes in the local temperature, salinity, and nutrient load. Water-quality changes and temperature variability resulting from such discharge can be estimated from observation in the visible-to-shortwave-infrared (VSWIR) and the mid- and thermal-infrared (TIR) regions, respectively. The processes of meltwater forming ponds and entering the sea have unique ecological characteristics and are of additional interest because they are also highly subject to climate change. HyspIRI can use TIR to observe the spatial distribution of meltwater, whereas its VSWIR spectrometer can be used to quantify the changes of phytoplankton pigments (e.g., chlorophyll a). Quantifying seamargin changes requires accurate delineation of margin positions wherein tidal influence is minimal. Since the HyspIRI VSWIR data cover a wide spectral range and offer high spatial resolution, they are particularly suitable for shoreline delineation/change detection, as well as flood mapping. The signal-to-noise ratio of HyspIRI is expected to be comparable to that of the Hyperspectral Imager for the Coastal Ocean and much higher than that of Hyperion and Landsat Enhanced Thermal Mapper Plus, making it suitable for studying optically complex coastal aquatic environments. Herein, using examples from existing satellite sensors, HyspIRI's potential to study these complex sea-margin processes is presented and discussed.

DISTRIBUTION OF THE MAJOR INORGANIC NUTRIENTS IN THE ROSS SEA, ANTARCTICA

2019-01-01T00:00:00Z

Title: DISTRIBUTION OF THE MAJOR INORGANIC NUTRIENTS IN THE ROSS SEA, ANTARCTICA Authors: Lee, BoYeon; Kim, Bo Kyung; Son, Wuju; La, Hyoung Sul; Kim, Jeong-Hoon; Ha, Sun-Yong Abstract: Despite high concentration of nutrients in ambient water, the Antarctic has low chlorophyll a where primary production is low compared to other regions on an annual basis. Our research region is the Ross Sea, known as one of the most productive polynya. We investigated spatial and temporal variations of nutrients to understand the environmental changes in the Ross Sea. Seawater sampling was carried out at 13 stations in 2018 (ANA08C, February 25 March 1) and 17 stations in 2019 (ANA09B, January 16 21). In 2018, the average concentrations of phosphate, nitrate + nitrite and silicate were 2.11 ±0.14, 20.94 ±1.22, and 74.34 ±13.45 μM, respectively. Overall, no significant difference was shown between 2018 and 2019, average concentrations of phosphate, nitrate + nitrite and silicate in 2019 were 1.97 ±0.22, 28.25 ±3.51, and 72.90 ±12.50 μM, respectively. Dissolved inorganic ammonium concentration remained low ranging from 0 to 1.56 μM (2018) and from 0 to 1.09 μM (2019) throughout the study region and it was just above the level of detection at some stations. We found high concentration of nutrients at the Ross Sea continental shelf. Consistent with our result, warm circumpolar deep water (CDW) intruded on the Ross Sea continental shelf and flowed toward the Ross sea ice shelf. This flow pattern suggests that the major nutrients seemed to be provided with intrusion of CDW.

Biochemical composition and the contributions of hydrolysable particulate organic matter in the Ross Sea, Antarctic Ocean

2019-01-01T00:00:00Z

Title: Biochemical composition and the contributions of hydrolysable particulate organic matter in the Ross Sea, Antarctic Ocean Authors: Kim, Bo Kyung; Jo, Na-eun; La, Hyoung Sul; Lee, BoYeon; Kim, Jeong-Hoon; Ha, Sun-Yong Abstract: Water (<100 m) samples were collected from the Ross Sea (Antarctica) in late February to early March 2018, with the aim of investigating the spatial distribution of biochemical composition (proteins; PRT, carbohydrates; CHO, and lipids; LIP) and bioavailability of particulate organic matter (POM). Overall, the biochemical composition of POM was dominated by CHO, which accounted for 58.8% (SD = ± 12.8%) of total POM concentration, followed by PRT(21.0 ± 11.3%) and LIP (20.2 ± 9.7%). The particulated hydrolysable PRT (HPRT) ranged from below the detection limit 0 to 56.7 μg/L, hydrolysable CHO (HCHO) from 7.6 to 121.0 μg/L, and hydrolysable LIP (HLIP) from 7.0 to 86.6 μg/L, respectively. As a result, HPRT, HLIP, and HCHO accounted for 67.9%, 37.8%, and 64.6% of each compound, respectively. These results showed that PRT and CHO were largely used as sources of energy for higher trophic levels in the Ross Sea. .

THE INFLUENCE OF PENGUIN EXCREMENT ON PHYTOPLANKTON PRODUCTION DURING SHORT-TERM INCUBATION IN THE ROSS SEA, ANTARCTICA

2019-01-01T00:00:00Z

Title: THE INFLUENCE OF PENGUIN EXCREMENT ON PHYTOPLANKTON PRODUCTION DURING SHORT-TERM INCUBATION IN THE ROSS SEA, ANTARCTICA Authors: Kim, Bo Kyung; Kim, Jeong-Hoon; Jung, Jin-Woo; Ha, Sun-Yong Abstract: Penguin rookeries in Antarctic coastal areas linked to marine ecosystems since their excretion has bio-available micronutrients and macronutrients for phytoplankton and potentially enhanced phytoplankton productivity and microbiota diversity. Penguin excrement samples were derived from three penguin rookeries (Cape Hallet; Cape, Edmonson point; Ep, and Inexpressible Island; Inex). To investigate the impact of penguin excretion, we conducted excrement-enrichment 13C and 15N dual-labelled phytoplankton incubation experiments with seawater samples collected from near the each penguin rookery in the Ross Sea, Antarctica. Specific carbon and nitrate uptake rates in control were higher than those of treatment during short-term incubation (4 hours), while the opposite was observed for specific ammonium uptake. These responses indicate that nitrate production by natural phytoplankton was regulated and inhibited by high ammonium concentrations from penguin excrement in the Ross Sea.