Effects of nutrient enrichment derived from fish farming activities on macroinvertebrate assemblages in a subtropical region of Hong Kong     

Gao QF  Cheung KL  Cheung SG  Shin PK 《Marine pollution bulletin》2005,51(8-12):994-1002

To study the correlation between nutrient enrichment derived from fish farming activities and changes in macrobenthic assemblages, a one-year field study was conducted in Kau Sai Bay marine fish culture zone of Hong Kong. Bimonthly sediment samples were collected at six stations: two at the fish cages, two near the boundary of the fish culture area, and two reference sites further away from the culture area. Sediment physico-chemical characteristics in terms of silt/clay fraction, moisture content, total organic carbon (TOC), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) were analyzed. The macrobenthos (>0.5 mm) present in the sediment were sorted, identified and enumerated. On average, TOC, TKN and TP levels at the fish cage stations were 82.8%, 128.5% and 1315.7% higher than those at the reference stations, respectively. As a result, the N:P molar ratio was greatly reduced from 8.75 at the reference stations to 1.83 at the fish cage stations. Univariate and multivariate analyses revealed that diversity of macrofauna was significantly reduced and community structure differed at the fish cage stations relative to the reference sites. The intermediary stations near the fish culture area showed a transitional state of disturbance. Faunal diversity was negatively correlated with nutrient level, reflecting the adverse impacts of nutrient enrichment derived from fish farming activities on the benthic assemblages. Whilst in subtropical Asia-Pacific trash fish is the major feed for fish culture resulting in a higher nutrient loading and nutrient ratio accumulated in the sediment beneath the fish rafts, the effects of nutrient enrichment on macrobenthic assemblages are comparable to that in temperate waters owing to relatively high sediment metabolism rate and smaller fish culture scale in Hong Kong.  相似文献   

Seasonal variability of benthic indices: an approach to test the applicability of different indices for ecosystem quality assessment     

Reiss H  Kröncke I 《Marine pollution bulletin》2005,50(12):1490-1499

In recent studies, several benthic biological indices were developed or used to assess the ecological quality status of marine environments. In the present study the seasonal variability of several univariate and multimetric indices was studied on a monthly scale (September 2000 until May 2002) in different areas of the North Sea such as the German Bight, the Oyster Ground and the Dogger Bank. The stations were chosen to reflect a gradient in the hydrographic regime, temperature and organic matter supply. The seasonal variability was highest for the univariate indices such as the Shannon–Wiener Index and the Hurlbert Index. Thus, due to sensitivity to recruitment the corresponding ecological status ranged from ‘good’ to ‘poor’ depending on the season. For the multimetric indices such as the AMBI or the BQI the seasonal variability and the corresponding ecological status were low. The results are discussed concerning possible consequences for ecological quality assessment especially related to the Water Framework Directive (WFD).  相似文献   

西双版纳橡胶种植特点及其对热带森林景观影响的遥感研究   总被引：5，自引：0，他引：5  

张佩芳  许建初  王茂新  邓喜庆 《国土资源遥感》2006,17(3):51-55

利用遥感技术研究西双版纳橡胶分布格局、时空动态及其对热带森林景观的影响。研究表明： 西双版纳橡胶种植既有明显的地域分布和地带分布差异特征，也有很高的时空动态度； 橡胶种植对土壤侵蚀作用不明显，但是使周边环境破碎度加大，热带森林异质性自然景观向单一人工斑块化景观发展； 西双版纳橡胶种植获得了巨大的社会效益和经济效益，也对热带森林的稳定性和多样性造成威胁。  相似文献   

Vertical Distribution of Bacteria in Doroninskoe Lake(Zabaikalie,Russia):Paradigm of Dominance     

Natalia BELKOVA  Evgeniya MATYUGINA 《《地质学报》英文版》2014,88(Z1):53-55

正1 Introduction Prokaryotes are key organisms in aquatic ecosystems as they play animportant role in the biogeochemical cycling of elements.Investigations on the relationships betweenthe diversity of microbial community and environmentalfactors offer useful information that bothleads to understanding of the process of element  相似文献   

A new dragonfly family from the mid Cretaceous Burmese amber (Odonata: Aeshnoptera: Burmaeshnidae)     

《Cretaceous Research》2017

The third Cretaceous Aeshnoptera in amber is described from Myanmar. It represents a new family Burmaeshnidae fam. nov., genus and species Burmaeshna azari gen. et sp. nov. Its exact affinities remain uncertain but it is probably the sister group of the Late Cretaceous family Enigmaeshnidae. This discovery supports the hypothesis of an intense period of appearance of many aeshnopteran subclades during the late Early Cretaceous and the Late Cretaceous.  相似文献