NIPR

Mitsuo Fukuchi - National Institute of Polar Research (Japan)

The National Institute of Polar Research (NIPR) was founded in 1973 as an inter-university research institute to carry out comprehensive scientific research and observations in polar regions. NIPR has been playing a major role in Japanese Antarctic research programs, specifically the Japanese Antarctic Research Expeditions (JARE), while pursuing cutting-edge studies in collaboration with other research communities relating to the earth, the environment, life, space and other fields. The Japanese Antarctic research programs have the history of more than 50 years and observations in polar regions are becoming increasingly important for monitoring and understanding the Earth environment. NIPR is intensively carrying out a wide range of activities in the Antarctic research programs both temporally and spatially through research using both advanced methods, plus long-term monitoring observations and field and ocean observations.

Deploying CPR from Shirase during sea trials in the sea of Japan.

One of the important long-term marine observations has been the annual JARE zooplankton net sampling conducted in the Indian Ocean sector of the Antarctic Ocean every austral summer since 1972 (JARE-14) using a NORPAC standard net fitted with 110μm and 330μm mesh. Daily routine observations are made on route through the Southern Ocean to and from the Japanese Antarctic station Syowa (69 00 S, 39 35E). These observations have focussed primarily on longitudes 110° and 150°E south of Australia. The observations included measurements of temperature and salinity using a CTD, plus phytoplankton collection and the NORPAC net. Observations were made initially on icebreaker Fuji, then Shirase and then its replacement also called Shirase.

The NORPAC net has been invaluable in demonstrating long-term inter-annual and inter-decadal cyclic patterns. However, because of the small size of the net coupled with net avoidance problems, and the large distances between sampling sites, it was noted that the NORPAC net was perhaps not ideal for long-term mapping and monitoring of changes in distribution or abundance in relation to the various oceanographic boundaries in the Southern Ocean. As a part of the monitoring programs in Antarctica, the NIPR has been operating a CPR survey on JARE voyages since 1999 (JARE-41), in order to augment the existing net sampling program and also to improve the interpretation of the data collected by NORPAC net. At the same time Japan became a major collaborator in the SCAR Southern Ocean CPR Survey and about 30% of the Southern Ocean CPR data is collected by Japan

Deploying CPR from Umitaka Maru in Antarctica

Six tows are made at the same time each year by Shirase along the 110° (December) and 150°E (March) transects. In addition, about 10 to 12 tows are now collected regularly by the TRV Umitaka Maru (Tokyo University of Marine Science and Technology) in the Southern Ocean south-east of Cape Town to south of Tasmania. Other opportunistic tows have been conducted in this region by Kaiyo Maru, Hakuho Maru and Tangaroa (on charter to NIPR), and Kaiyo Maru has conducted tows across Drake Passage in 2000 close to Sir Alister Hardy's original 1927 tows. A comparison of the tows by Kaiyo Maru with Hardy's results indicates a possible shift in the dominance of species from abundant large copepod species and chaetognaths in 1927 to smaller copepods, notably Oithona, and other species in 2000.

More recently the Japanese CPR tows together with those from Australia in SO-CPR survey showed a large increase of foraminiferans in the eastern Antarctic region in the austral summer of 2004/05. Abundances ranged from 50 to about 80% of total numbers, well above the long-term average of about 8%, with an associated decrease in the abundance of other species. This bloom appeared to be associated with an elevated average chlorophyll a biomass in 2005. We do not know the effect of this large bloom on the rest of the Antarctic marine ecosystem, but it is essential that we continue the long-term monitoring of plankton and especially calcareous species like foraminiferans as they may be affected by ocean acidification.