Entanglement of Antarctic fur seals at Bouvetøya, Southern Ocean

Entanglements of Antarctic fur seals Arctocephalus gazella were recorded during four summers from 1996 to 2002 at the subantarctic island, Bouvetøya. Rates of entanglement varied between 0.024% and 0.059%. These rates are low for a pinniped population and might be because of the geographic isolation of the haulout site. An apparent decrease in the levels of entanglement over the course of the study was likely due, at least in part, to the removal of entanglements by observers. At least two-thirds of entangling materials were generated by fishery sources. Since there is no known local source of anthropogenic marine pollution, seals become entangled either in waters distant from the island, or when materials drift into local waters. Significantly more subadults were found entangled than expected from the postulated population age class distribution.     

Physiological effects of hypercapnia in the deep-sea bivalve Acesta excavata (Fabricius, 1779) (Bivalvia; Limidae)

The option of storing CO₂ in subsea rock formations to mitigate future increases in atmospheric CO₂ may induce problems for animals in the deep sea. In the present study the deep-sea bivalve Acesta excavata was subjected to environmental hypercapnia (pHSW 6.35, PCO₂ = 33,000 μatm) corresponding to conditions reported from natural CO₂ seeps. Effects on acid–base status and metabolic rate were related to time of exposure and subsequent recovery. During exposure there was an uncompensated drop in both hemolymph and intracellular pH. Intracellular pH returned to control values, while extracellular pH remained significantly lower during recovery. Intracellular non-bicarbonate buffering capacity of the posterior adductor muscle of hypercapnic animals was significantly lower than control values, but this was not the case for the remaining tissues analyzed. Oxygen consumption initially dropped by 60%, but then increased during the final stages of exposure, which may suggest a higher tolerance to hypercapnia than expected for a deep-living species.     

对流层中高层的锋生过程

1.引言在本文中,我们仔细研究了高空锋生的基本问题:i)模式中几何因素(例如β-平面和球面)对模拟锋生有多大程度影响,ii)高空锋生是否基本上是一个二维过程,iii)在高空锋区的发展中,是否有正反馈机制起作用.我们的研究方案采用三维原始方程模式,对不稳定斜压波生命史进行模拟,然后详细分析其结果.     

Metal uptake in zebrafish embryo-larvae exposed to metal-contaminated sediments

Heavy metal contamination in coastal and estuarine regions of inner Tolo Harbour, as well as some river and nullah areas, is one of the major water-pollution issues in Hong Kong. Zebrafish (Danio rerio) embryo-larvae was used to study metal uptake from coastal sediments collected from Fo Tan River (industrial area, Sha Tin), Tai Po River (residential area, Tai Po) and Wu Kai Sa (rural area, Tolo Harbour). Exposure experiments (7-days) were carried out using different concentrations (0.1%, 0.5%, 1% and 0% as control) of sediments that were added to aquaria containing fertilized zebrafish eggs until they hatched to become larvae. Uptake of heavy metals (Cd, Cu, Pb and Zn) was determined in whole embryo-larvae following exposure. Significant levels of Cd, Cu, Pb and Zn were detected in the embryo-larvae exposed to sediments from Tai Po River. However, significant levels of only Cd and Cu were found in embryo-larvae exposed to sediments from Fo Tan River.