Mass, nitrogen content, and decomposition of woody debris in forest stands affected by excreta deposited in nesting colonies of Great Cormorant

First online: 14 March 2015Great Cormorant (Phalacrocorax carbo), a piscivorous bird, has established breeding colonies in a coniferous forest near Lake Biwa in central Japan. This study investigated the possible effects of the colony’s excreta on the mass, nitrogen (N) content, and decomposition of woody debris. Study plots were established in forest stands representing four stages from breeding colony establishment to post-abandonment. The mass of fallen branches (diameter 1–5 cm) and coarse woody debris (logs, snags, and stumps; diameter ≥10 cm) was greater in forest stands colonized by Cormorants than a control stand never colonized by Cormorants. This was primarily attributed to Cormorant activity that caused increased mortality of standing trees and by Cormorants breaking branches for nesting materials. Nitrogen content of branches and logs that had fallen to the forest floor was negatively correlated with the relative density of wood. Nitrogen content of branches was consistently higher (at a given value of relative density) in the colonized stands than in the control stand. The increase of branch N content was possibly caused by the incorporation of N into decomposing branches with excreta-derived N supplied as throughfall and/or soil solution. The mean value of 2-year mass loss of recently dead branches and logs was significantly greater for woody debris in the smallest diameter class but was not significantly different among the forest stands. This suggests that the excessive supply of excreta-derived N and concomitant enrichment of N in soil had negligible effects on the initial stages of decomposition of woody debris

Field measurements of absolute gravity in East Antarctica

This paper reports the results of field-based absolute gravity measurements aimed at detecting gravity change and crustal displacement caused by glacial isostatic adjustment. The project was initiated within the framework of the 53rd Japanese Antarctic Research Expedition (JARE53). Absolute gravity measurements, together with GPS measurements, were planned at several outcrops along the Prince Olav Coast and Sôya Coast of East Antarctica, including at Syowa Station. Since the icebreaker Shirase (AGB 5003) was unable to moor alongside Syowa Station, operations were somewhat restricted during JARE53. However, despite this setback, we were able to complete measurements at two sites: Syowa Station and Langhovde. The absolute gravity value at the Syowa Station IAGBN (A) site, observed using an FG-5 absolute gravimeter (serial number 210; FG-5 #210), was 982 524 322.7±0.1 μGal, and the gravity change rate at the beginning of 2012 was –0.26 μGal∙a-1. An absolute gravity value of 982 535 584.2±0.7 μGal was obtained using a portable A-10 absolute gravimeter (serial number 017; A-10 #017) at the newly located site AGS01 in Langhovde

ムセン LAN ヲ モチイタ GPSデータ エンカク カイシュウ システム ノ カイハツ

無線LANを利用した2周波GPSデータ遠隔回収システムを開発した.このシステムは,GPSロガーとデータ送信装置からなる地上観測装置とデータ回収装置で構成され,コマンド送受信にはZigBee通信(2.4 GHz, 250 Kbps)を, GPSデータの送受信には無線LAN通信(2.4 GHz, 54 Mbps)を使用する.GPSロガーで収録された1秒サンプリングデータから毎日作成される30秒サンプリングデータファイルが送信される. これまで,(1)地上でのデータ回収試験,(2) 小型無人飛行機によるデータ回収試験,(3) 昭和基地・西の浦での実データ回収試験を実施した.(1) では,最大400 m 程度の距離で全データを回収でき,(2) では約250 m 以下の高さで飛行する飛行機により約24.5 MB のデータを回収できた.(3) では,10 分以内に約23.5 MB のGPS ブイデータの回収に成功しており,観測を止めることなくデータ回収が可能となった.A remote retrieval system, using a wireless LAN, was developed to retrieve dual-frequency GPS data. The system consists of a ground observation unit (comprising a dual-frequency GPS logger and a data transmission unit) and a data retrieval unit. In this system, we use the ZigBee communication protocol to transmit control commands (2.4 GHz, 250 Kbps) and a wireless LAN communication to transmit GPS data (2.4 GHz, 54 Mbps). Data of every 30 seconds to transmit to the data retrieval unit are re-sampled from 1-second data at 00 UT each day. We conducted three data-transmission tests with the system: (1) a ground data retrieval test, (2) a data retrieval test from the atmosphere of a few hundred meters high using a small unmanned aircraft, and (3) actual GPS-data retrieval tests from a GPS buoy deployed on sea ice at Nisi-no-ura Cove, Syowa Station, Antarctica. In test (1), we successfully received all the data from the ground observation unit when situated at distances of less than 400 m from the data retrieval unit. In test (2), we obtained approximately 24.5 MB of data from the aircraft at heights of less than 250 m. In test (3), we obtained approximately 23.5 MB of data from the GPS buoy within 10 minutes. The proposed system has the advantage of enabling continuous measurements without aborting the measurement at the data retrievals

第53次日本南極地域観測隊で新設した重力基準点

第53 次日本南極地域観測隊では，昭和基地の国際絶対重力基準点（IAGBN（A）点）およびラングホブデの露岩で絶対重力測定と相対重力測定を行った．これに伴い，昭和基地に2点，ラングホブデに5点の重力基準点を新たに設置した．本稿では，新設した各重力基準点の位置および重力値を含む詳細情報を記載する．Absolute and relative gravity measurements were carried out at International Absolute Gravity Basement Network (IAGBN (A)) site #0417 at Syowa Station and at outcrops at Langhovde during the summer operation of the 53rd Japanese Antarctic Research Expedition (JARE-53). Two new gravity reference sites were established at Syowa Station and five at Langhovde. We present detailed data for the new sites, including location coordinates and gravity values

Brief overview of the absolute gravity measurement conducted in JARE53

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月30日（金） 国立極地研究所 ３階ラウン

Development of GPS data remote retrieval system using wireless LAN

A remote retrieval system, using a wireless LAN, was developed to retrieve dual-frequency GPS data. The system consists of a ground observation unit (comprising a dual-frequency GPS logger and a data transmission unit) and a data retrieval unit. In this system, we use the ZigBee communication protocol to transmit control commands (2.4 GHz, 250 Kbps) and a wireless LAN communication to transmit GPS data (2.4 GHz, 54 Mbps). Data of every 30 seconds to transmit to the data retrieval unit are re-sampled from 1-second data at 00 UT each day. We conducted three data-transmission tests with the system: (1) a ground data retrieval test, (2) a data retrieval test from the atmosphere of a few hundred meters high using a small unmanned aircraft, and (3) actual GPS-data retrieval tests from a GPS buoy deployed on sea ice at Nisi-no-ura Cove, Syowa Station, Antarctica. In test (1), we successfully received all the data from the ground observation unit when situated at distances of less than 400 m from the data retrieval unit. In test (2), we obtained approximately 24.5 MB of data from the aircraft at heights of less than 250 m. In test (3), we obtained approximately 23.5 MB of data from the GPS buoy within 10 minutes. The proposed system has the advantage of enabling continuous measurements without aborting the measurement at the data retrievals

New gravity reference sites established during JARE-53

Absolute and relative gravity measurements were carried out at International Absolute Gravity Basement Network (IAGBN (A)) site #0417 at Syowa Station and at outcrops at Langhovde during the summer operation of the 53rd Japanese Antarctic Research Expedition (JARE-53). Two new gravity reference sites were established at Syowa Station and five at Langhovde. We present detailed data for the new sites, including location coordinates and gravity values