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The Atlantic hurricanes of 1999 caused widespread environmental damage throughout the Caribbean and US mid-Atlantic coastal regions. However, these storms also proved beneficial to certain microbial habitats; specifically, cyanobacteria-dominated mats. Modern mats represent the oldest known biological communities on earth, stromatolites. Contemporary mats are dominant biological communities in the hypersaline Bahamian lakes along the Atlantic hurricane track. We examined the impacts of varying levels of hypersalinity on 2 processes controlling mat growth, photosynthesis and nitrogen fixation, in Salt Pond, San Salvador Island, Bahamas. Hypersalinity (> 5 times seawater salinity) proved highly inhibitory to these processes. Freshwater input from Hurricane Floyd and other large storms alleviated this salt-inhibition. A predicted 10 to 40 year increase in Atlantic hurricane activity accompanied by more frequent "freshening" events will enhance mat productivity, CO2 sequestration and nutrient cycling. Cyanobacterial mats are sensitive short- and long-term indicators of climatic and ecological changes impacting these and other waterstressed environments. 相似文献
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The biology of Octopus vulgaris Cuvier inhabiting subtropical littoral reefs off the east coast of South Africa was investigated. Analyses of stomach contents and lair middens revealed that the mussel Perna perna was the dominant food organism. Growth rate of captive individuals was higher than has previously been recorded but food conversion was lower. Females became sexually mature at 900 g which is estimated to be attained in 3.6 months. Males became sexually mature at 400 g, which is estimated to be attained after 3 months. Results indicate that females live for 9–12 months and have the potential to reach 4 000 g in 240 d while males live for about 12–15 months and have the potential to achieve 4 000 g in 290 d. Mating and breeding occurred throughout the year although evidence for the seasonal migration of females is presented and discussed in relation to breeding and feeding behaviour. 相似文献
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A sand column leaching system with well-controlled suction and flow rate was built to investigate the effects on bacterial transport of air-water interface effects (AWI) correlated to water content, particle size, and column length. Adsorption of Escherichia coli strain D to silica sands was measured in batch tests. The average % adsorption for coarse and fine sands was 45.9+/-7.8% and 96.9+/-3.2%, respectively. However, results from static batch adsorption experiments have limited applicability to dynamic bacterial transport in columns. The early breakthrough of E. coli relative to bromide was clear for all columns, namely c. 0.15 to 0.3 pore volume earlier. Column length had no significant effects on the E. coli peak concentration or on total recovery in leachate, indicating retention in the top layer of sands. Tailing of breakthrough curves was more prominent for all fine sand columns than their coarse sand counterparts. Bacterial recovery in leachate from coarse and saturated sand columns was significantly higher than from fine and unsaturated columns. Observed data were fitted by the convection-dispersion model, amended for one-site and two-site adsorption to particles, and for air-water interface (AWI) adsorption. Among all models, the two-site+AWI model achieved consistently high model efficiency for all experiments. Thus it is evident from experimental and modeling results that AWI adsorption plays an important role in E. coli transport in sand columns. 相似文献
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引言 当蒸发损失的水分大于补充的淡水时,盐浓度将超过正常海水浓度(大约35psu),就出现了高盐度的情况,处于高盐胁迫下的活组织遭受严重的水胁迫、渗透压压迫及干燥的威胁[1~5].长期的盐胁迫作用,形成了这些生物系统中的特定的生物区系[1~5]. 相似文献
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Cesar Rodriguez-Saona Therese M. Poland James R. Miller Lukasz L. Stelinski Gary G. Grant Peter de Groot Linda Buchan Linda MacDonald 《Chemoecology》2006,16(2):75-86
Summary. We investigated the volatile emissions of Manchurian ash seedlings, Fraxinus mandshurica, in response to feeding by the emerald ash borer, Agrilus planipennis, and to exogenous application of methyl jasmonate (MeJA). Feeding damage by adult A. planipennis and MeJA treatment increased volatile emissions compared to unexposed controls. Although the same compounds were emitted
from plants damaged by beetles and treated with MeJA, quantitative differences were found in the amounts of emissions for
individual compounds. Adult virgin female A. planipennis were similarly attracted to volatiles from plants damaged by beetles and those treated with MeJA in olfactometer bioassays;
males did not respond significantly to the same volatiles. Coupled gas chromatographic-electroantennogram detection (GC-EAD)
revealed at least 16 antennally-active compounds from F. mandshurica, including: hexanal, (E)-2-hexenal, (Z)-3-hexen-1-ol, 3-methyl-butylaldoxime, 2-methyl-butylaldoxime, (Z)-3-hexen-1-yl acetate, hexyl acetate, (E)-β-ocimene, linalool, 4,8-dimethyl-1,3,7-nonatriene, and E,E-α-farnesene. Electroantennogram (EAG) dose–response curves using synthetic compounds revealed that females had a stronger
EAG response to linalool than males; and male responses were greater to: hexanal, (E)-2-hexenal, (Z)-3-hexen-1-ol, 3-methyl-butylaldoxime, 2-methyl-butylaldoxime, and hexyl acetate. These results suggest that females may
use induced volatiles in long-range host finding, while their role for males is unclear. If attraction of females to these
volatiles in an olfactometer is upheld by field experiments, host plant volatiles may find practical application in detection
and monitoring of A. planipennis populations. 相似文献
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Russell C. Van Horn Jason C. Buchan Jeanne Altmann Susan C. Alberts 《Behavioral ecology and sociobiology》2007,61(12):1823-1837
Group living provides benefits to individuals while imposing costs on them. In species that live in permanent social groups,
group division provides the only opportunity for nondispersing individuals to change their group membership and improve their
benefit to cost ratio. We examined group choice by 81 adult female savannah baboons (Papio cynocephalus) during four fission events. We measured how each female’s group choice was affected by several factors: the presence of
her maternal kin, paternal kin, age peers, and close social partners, her average kinship to groupmates, and her potential
for improved dominance rank. Maternal kin, paternal kin, and close social partners influenced group choice by some females,
but the relative importance of these factors varied across fissions. Age peers other than paternal kin had no effect on group
choice, and average kinship to all groupmates had the same effect on group choice as did maternal kin alone. Most females
were subordinate to fewer females after fissions than before, but status improvement did not drive female group choice; females
often preferred to remain with social superiors who were their close maternal kin, rather than improving their own social
ranks. We suggest that during permanent group fissions, female baboons prefer to remain with close maternal kin if those are
abundant enough to influence their fitness; if they have too few close maternal kin then females prefer to remain with close
paternal kin, and social bonds with nonkin might also become influential.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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