排序方式: 共有6条查询结果,搜索用时 0 毫秒
1
1.
The secondary production of the eusirid amphipod Pontogeneia rostrata Gurjanova, 1938, was examined on a sandy shore in Korea. Secondary production was estimated using a size-frequency method.
The biomass structure of P. rostrata included one peak in spring, with maximum biomass occurring in April. The annual secondary production of this species was
0.57 g DW m−2 yr−1 with an annual P/B ratio of 6.97. Secondary production of P. rostrata fell within the range observed for other amphipods on intertidal sandy shores, although the production/biomass (P/B) ratio
was higher than those recorded previously from the sampling site and from other tidal and estuary areas, as the number of
generations increases the P/B ratio. The results showing high abundance and P/B ratios suggest that P. rostrata plays an important role in the sandy shore ecosystem as a trophic link between primary producers and higher consumers. 相似文献
2.
We investigated the seasonal variation of the neustonic zooplankton community in the surface layer (above 30 cm in depth) of 16 stations in southern waters of Korea from April 2002 to April 2003. In the neustonic community, copepods accounted for 59% of total organisms, as the most predominant group, while other dominant groups were invertebrate larvae, cladocerans, tunicates and fish eggs. Pontellid copepods, a major group of neustonic zooplankton, showed a marked seasonal variation and displayed a significant positive correlation with temperature (P < 0.05). Fish eggs appeared from spring to early summer in the inshore waters while tunicates and oceanic copepods (Eucalanus spp. and Euchaeta spp.) were dominant in the offshore waters during high temperature periods. This suggests that the distribution pattern of the neustonic zooplankton is seasonally affected by the hydrological conditions of in- and offshore waters. The abundance of zooplankton was higher in the surface layer (< 15 cm) than in the subsurface layer (15–30 cm), and was also higher at night than during the daytime. Of the dominant copepod families, the density of acartiid and pontellid copepods was higher in the surface layer than the subsurface layer. The density of acartiid and corycaeid copepods was significantly higher during daytime than nighttime. This indicates that the surface layer in temperate regions may provide a favorable habitat for neustonic copepods despite the dynamic environmental fluctuations. 相似文献
3.
Ocean Science Journal - Estuaries are one of the most productive regions in ecosystems and serve as important nursery and recruitment habitats for various living resources. However, information on... 相似文献
4.
5.
Euchaetid copepods (Calanoida, Clausocalanoidea) were collected from the southeastern region of Korea and the East/Japan Sea
from June 2007 to August 2008. Seven species were found and redescribed in this study: five species from the genus Euchaeta (E. concinna, E. indica, E. longicornis, E. plana and E. rimana) and two species from the genus Paraeuchaeta (P. elongata and P. russelli). Using scanning electron microscopy, we observed detailed taxonomic features with special references to their genital structure.
The euchaetid copepods show speciesspecific characteristics on their genital structures, in particular on the shapes of genital
operculum and genital flange. Their zoogeographies were also discussed. They can be regarded as an indicator species of the
Tsushima Warm Current and East Sea Intermediate Water. 相似文献
6.
Reproductive patterns of an epifaunal amphipod,Pontogeneia rostrata, were studied on Dolsando sandy shore in Korea. The life history pattern was iteroparous, with recruitment mainly occurring
from winter to spring. The sex ratio was male-biased, especially during breeding periods. The mean body length of females
was significantly larger than that of males. Brood size and egg volume were positively related to the body length of ovigerous
females. There was no significant difference in brood size between successive breeding periods, but egg volumes were significantly
higher in early winter (December) than in late spring breeding (May and June), increasing the probability of survival to hatching.
These traits contribute to more reproductive potential in early winter than in late spring breeding. The mean brood size of
epifaunalP. rostrata was larger but the mean egg volume smaller than that of infaunal amphipods in this sampling area. We suggest that reproductive
effort for epifaunal species may be proportionally greater than for infaunal species in risky environments. 相似文献
1