Respiration rates of tropical Atlantic copepods from the Cape Verde Islands

Copepods were sampled at two sampling sites off the island of São Vicente, Cape Verde Archipelago, in spring (March/April) and early summer (May/June) of 2010. The two sampling sites were located in Mindelo Bay (16.90N, 25.01W; bottom depth 22 m) and around 8 km off the town of São Pedro (16.77N, 25.12W; bottom depth 800 m). Samples were collected on board the local fishing vessel 'Sinagoga' using a WP-2 net (Hydrobios, 0.26 m**2 mouth opening, 200 µm mesh size). The net was either applied as a driftnet, drifting for 10 min in 22 to 0 m depth below the surface, or it was towed vertically with a towing speed of 0.5 m/s**1. For stratified sampling, the net was deployed in repetitive hauls from 560 to 210 m, from 210 to 80 m, and from 80 to 0 m in March/April and from 600 to 300 m, 300 to 100 m, and 100 to 0 m in May/June. Additional depth-integrated hauls were conducted from 600-0 m or 500-0 m during both field campaigns. Respiration rates of epi- and mesopelagic calanoid copepods were measured in the land-based laboratory at the Instituto Nacional de Desenvolvimento das Pescas (INDP) in Mindelo. Oxygen consumption was measured non-invasively by optode respirometry at three different ambient temperatures (13, 18, and 23°C) with a 10-channel oxygen respirometer (Oxy-10 Mini, PreSens Precision Sensing GmbH, Regensburg, Germany). All experiments were run in darkness in temperature-controlled incubators (LMS Cooled Incubator Series 1A, Model 280) equipped with water baths to ensure constant temperatures throughout the experiments, tolerating a variation of ±1°C.

2010年春季（3月/4月）与初夏（5月/6月），研究团队于佛得角群岛圣维森特岛周边两处采样点采集桡足类（Copepods）样本。两处采样点分别为明德卢湾（坐标16.90°N，25.01°W，底栖水深22米），以及圣佩德罗镇外约8公里海域（坐标16.77°N，25.12°W，底栖水深800米）。样本采集工作在当地渔船“Sinagoga”号上完成，使用WP-2网（Hydrobios公司生产，网口开口面积0.26㎡，网孔孔径200μm）。该网具可采用两种作业模式：一是作为流刺网，在表层下22至0米水深漂流10分钟；二是以0.5m/s的拖速进行垂直拖曳。分层采样环节中，3月/4月的采样网按560~210米、210~80米、80~0米的水层区间进行重复拖网；5月/6月则调整为600~300米、300~100米、100~0米的水层区间。两次野外调查期间，还额外开展了全水层集成拖网作业，采样水深范围为600~0米或500~0米。表水层与中层浮游哲水蚤目（calanoid copepods）桡足类的呼吸速率，于明德卢的国家渔业发展研究所（Instituto Nacional de Desenvolvimento das Pescas, INDP）陆地实验室中测定。耗氧率采用无创光学探针呼吸测定法（optode respirometry），使用德国雷根斯堡PreSens Precision Sensing GmbH公司生产的10通道氧气呼吸仪（Oxy-10 Mini），在13℃、18℃、23℃三种环境温度下完成测量。所有实验均在配备水浴恒温系统的控温培养箱（LMS Cooled Incubator Series 1A，型号280）中于黑暗环境下开展，以确保实验全程温度恒定，温度波动控制在±1℃以内。