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Havenhand JN 《Ambio》2012,41(6):637-644
Increasing partial pressure of atmospheric CO2 is causing ocean pH to fall—a process known as ‘ocean acidification’. Scenario modeling suggests that ocean acidification in the Baltic Sea may cause a ≤3 times increase in acidity (reduction of 0.2–0.4 pH units) by the year 2100. The responses of most Baltic Sea organisms to ocean acidification are poorly understood. Available data suggest that most species and ecologically important groups in the Baltic Sea food web (phytoplankton, zooplankton, macrozoobenthos, cod and sprat) will be robust to the expected changes in pH. These conclusions come from (mostly) single-species and single-factor studies. Determining the emergent effects of ocean acidification on the ecosystem from such studies is problematic, yet very few studies have used multiple stressors and/or multiple trophic levels. There is an urgent need for more data from Baltic Sea populations, particularly from environmentally diverse regions and from controlled mesocosm experiments. In the absence of such information it is difficult to envision the likely effects of future ocean acidification on Baltic Sea species and ecosystems. 相似文献
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Sperm motility and longevity in the giant cuttlefish, Sepia apama (Mollusca: Cephalopoda) 总被引:1,自引:1,他引:1
The sperm kinetics and fertilisation literature in marine invertebrates is heavily biased toward free-spawning species. Nonetheless,
many species (e.g. cephalopods) transfer and/or fertilise gametes in confined external spaces or internally, creating very
different selective pressures on sperm storage, sperm longevity and hence sperm competition. Here we report the results of
an investigation into the effects of sperm age, water temperature and sperm concentration on sperm motility in the giant cuttlefish
(Sepia apama). Significant positive correlations were found between percent motility and sperm concentration, and between sperm motile
speed and sperm concentration. Mean percent motility of cuttlefish sperm suspension was still 9% eight hours after being released
from the spermatophore and diluted into filtered seawater at 12°C (ambient field temperature during the spawning season).
Sperm resuspended from spermatangia taken from (mated) females in the field were motile for up to 100 hours. When spermatophores
were stored at 4°C motility was still observed in resuspended sperm after two months. Our results show that spermatangia and
spermatophores can retain and release live sperm for long periods. The observed longevity of sperm in S. apama greatly increases the potential for sperm competition in this species. 相似文献
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Chromosome preparations from gill tissue of the Australian flat oyster Ostrea angasi Sowerby were studied with conventional Giemsa staining, C-banding and silver staining techniques. A diploid complement of
2n = 20 was observed, consisting of five metacentric, three submetacentric and two subtelocentric pairs. Constitutive heterochromatin
was distributed as large centromeric blocks in Chromosome Pairs 3, 6, 8, 9 and 10. The nucleolus organizer regions (NORs)
were located terminally on long arms of Chromosome Pairs 9 and 10. This allowed the identification of homologous chromosomes
in submetacentric and subtelocentric pairs. Intraspecific variability in NOR pattern as revealed by differences in the number
of silver-stained NORs (Ag-NORs) per cell was found to be very common. Comparison of the patterns of karyotype, C-band and
Ag-NORs between species of the larviparous oysters for which data have been published demonstrate that the chromosomal structure
of the endemic Australian and New Zealand species O. angasi shows little similarity to the Southern Hemisphere oysters O. (Eostrea)puelchana Orbigny and Tiostrea chilensis (Philippi) and the Indo-West Pacific oyster O. denselamellosa, but very high resemblance to the European species O. edulis.
Received: 12 August 1996 / Accepted: 16 September 1996 相似文献
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