Phytoplankton biomass and primary production in the marginal ice zone of the northwestern Weddell Sea during austral summer

• Published in: Polar biology Vol. 21; no. 4; pp. 251 - 261
• Main Authors: MYUNG GIL PARK, SUNG RYULL YANG, KANG, S.-H, KYUNG HO CHUNG, JAE HYUNG SHIM
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 23.03.1999; Berlin Springer Nature B.V
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biogeography; Biological and medical sciences; Biomass; Euphotic zone; Fundamental and applied biological sciences. Psychology; Hydrography; Marine; Marine biology; Meltwater; Nutrient concentrations; Oceanography; Phytoplankton; Plankton; Primary production; Sea ice; Sea water ecosystems; Synecology; Water column; Weddell Sea; Southern Ocean; PSW, Weddell Sea; Primary productivity; Temperature; Environmental factor; Summer; Biomass; Depth; Marine environment; Plankton; Cyanobacteria; Bacteria; Phytoplankton; Polar region; Silicon; Thallophyta; Macronutrient(mineral); Algae; Vertical distribution; Phosphorus; Nitrogen; Chlorophyll a; Salinity; Photosynthetic pigment; Bloom; Nutrient; Sea ice
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s003000050360

During the austral summer of 1995, distributions of phytoplankton biomass (as chlorophylla), primary production, and nutrient concentrations along two north-south transects in the marginal ice zone of the northwestern Weddell Sea were examined as part of the 8th Korean Antarctic Research Program. An extensive phytoplankton bloom, ranging from 1.6 to 11.2mgm^sup -3^ in surface chlorophylla concentration, was encountered along the eastern transect and extended ca. 180km north of the ice edge. The spatial extent of the bloom was closely related to the density field induced by the input of meltwater from the retreating sea ice. However, the extent (ca. 200km) of the phytoplankton bloom along the western transect exceeded the meltwater-influenced zone (ca. 18km). The extensive bloom along the western transect was more closely related to local hydrography than to the proximity of the ice edge and the resulting meltwater-induced stability of the upper water column. In addition, the marginal ice zone on the western transect was characterized by a deep, high phytoplankton biomass (up to 8mg Chlam^sup -3^) extending to 100-m depth, and the decreased nutrient concentration, which was probably caused by passive sinking from the upper euphotic zone and in situ growth. Despite the low bloom intensity relative to the marginal ice zone in both of the transects, mean primary productivity (2.6gCm^sup -2^day^sup -1^) in shelf waters corresponding to the northern side of the western transect was as high as in the marginal ice zone (2.1gCm^sup -2^day^sup -1^), and was 4.8 times greater than that in open waters, suggesting that shelf waters are as highly productive as the marginal ice zone. A comparison between the historical productivity data and our data also shows that the most productive regions in the Southern Ocean are shelf waters and the marginal ice zone, with emerging evidence of frontal regions as another major productive site.[PUBLICATION ABSTRACT]