Monthly samples were collected in oceanic waters off Discovery Bay, Jamaica, in 60- and 200-m vertical hauls, using 200- and 64-m mesh plankton nets, from June 1989 to July 1991. Sixty-nine species of copepods were identified: nauplii, copepodites and adults were separately enumerated. Total copepod abundances (all stages) ranged from 695 to 4120 m-3 in the upper 60 m, and from 483 to 3319 m-3 in the 200-m water column, without any clear seasonal pattern. With the exception of temperature, no seasonal variations in physico-chemical (chlorophyll a, S, particulate organic carbon, particulate protein) or biological variables were evident. Nauplii, adults and copepodites of selected taxa, and two chaetognath species, showed no significant variations in body length. Significant variantions in reproductive index were detected for several species, but without seasonal trends; many species appear to be continuous or intermittent breeders. There was no evidence of seasonal pattern in overall community composition or diversity, or evidence of changes due to water mass advection. The copepod community can be divided into a recurrent group of 13 (at 60 m) to 17 (at 200 m) perennial species, present year-round, and associated ephemeral groups of 1 to 3 species, present randomly for 1 to 4 consecutive months. The most plausible explanation of these patterns is that broad areas of the Caribbean Sea are dominated by the community of perennial species, while the ephemeral species represent the superimposed influence of local mesoscale gyres. 相似文献
Motivated by shallow ocean waves propagating over coral reefs, we investigate the drift velocities due to surface wave motion in an effectively inviscid fluid that overlies a saturated porous bed of finite depth. Previous work in this area either neglects the large-scale flow between layers (Phillips in Flow and reactions in permeable rocks, Cambridge University Press, Cambridge, 1991) or only considers the drift above the porous layer (Monismith in Ann Rev Fluid Mech 39:37–55, 2007). Overcoming these limitations, we propose a model where flow is described by a velocity potential above the porous layer and by Darcy’s law in the porous bed, with derived matching conditions at the interface between the two layers. Both a horizontal and a novel vertical drift effect arise from the damping of the porous bed, which requires the use of a complex wavenumber k. This is in contrast to the purely horizontal second-order drift first derived by Stokes (Trans Camb Philos Soc 8:441–455, 1847) when working with solely a pure fluid layer. Our work provides a physical model for coral reefs in shallow seas, where fluid drift both above and within the reef is vitally important for maintaining a healthy reef ecosystem (Koehl et al. In: Proceedings of the 8th International Coral Reef Symposium, vol 2, pp 1087–1092, 1997; Monismith in Ann Rev Fluid Mech 39:37–55, 2007). We compare our model with field measurements by Koehl and Hadfield (J Mar Syst 49:75–88, 2004) and also explain the vertical drift effects as documented by Koehl et al. (Mar Ecol Prog Ser 335:1–18, 2007), who measured the exchange between a coral reef layer and the (relatively shallow) sea above.
Abstract: The purpose of this study was to validate the application of an invertebrate community index (ICI) to assess the biological integrity of urban streams. Validation involved comparing chemical and habitat data to ICI scores from 20 urban streams and four least‐impacted streams in the Choctawhatchee and Pea River watersheds located in Southeast Alabama. Chemical and habitat data were collected to support whether the ICI accurately predicts the health of the streams. A significant difference between urban and least‐impacted ICI scores, habitat evaluation scores, chemical variables, taxa richness, and Shannon‐Wiener diversity were observed when urban sites were compared with least‐impacted sites using Mann‐Whitney U‐test. Urban sites having low ICI scores, low species richness and diversity, and poor habitat showed greater impairment than least‐impacted sites. Cluster analysis of macroinvertebrate assemblages indicated two clusters. Significant differences between clusters in habitat evaluations, chemical parameters, and ICI scores showed that some urban sites were more degraded than other urban sites in the study. Differentiation between least‐impacted and urban sites indicated that the ICI provided valid biotic assessments. Therefore, this study validated that the ICI is capable of predicting the biological integrity of urban streams in the Choctawhatchee and Pea River watersheds. 相似文献
Water pollution from small rural industries is a serious problem throughout China. Over half of all river sections monitored for water quality are rated as being unsafe for human contact, and this pollution is estimated to cost several per cent of GDP. While China has some of the toughest environmental protection laws in the world, the implementation of these laws in rural areas is not effective. This paper explains the reasons for this implementation gap. It argues that the factors that have underpinned the economic success of rural industry are precisely the same factors that cause water pollution from rural industry to remain such a serious problem in China. This means that the control of rural water pollution is not simply a technical problem of designing a more appropriate governance system, or finding better policy instruments or more funding. Instead, solutions lie in changes in the model that underpins rural development in China. 相似文献
International aid is increasingly focused on adaptation to climate change. At recent meetings of the parties to the United Nations Framework Convention on Climate Change, the developed world agreed to rapidly increase international assistance to help the developing world respond to the impacts of climate change. In this paper, we examine the decision-making challenges facing internationally supported climate change adaptation projects, using the example of efforts to implement coastal protection measures (e.g. sea walls, mangrove planting) in Kiribati. The central equatorial Pacific country is home to the Kiribati Adaptation Project, the first national-level climate change adaptation project supported by the World Bank. Drawing on interview and document research conducted over an 8-year period, we trace the forces influencing decisions about coastal protection measures, starting from the variability and uncertainty in climate change projections, through the trade-offs between different measures, to the social, political, and economic context in which decisions are finally made. We then discuss how sub-optimal adaptation measures may be implemented despite years of planning, consultation, and technical studies. This qualitative analysis of the real-world process of climate change adaptation reveals that embracing a culturally appropriate and short-term (~20 years) planning horizon, while not ignoring the longer-term future, may reduce the influence of scientific uncertainty on decisions and provide opportunities to learn from mistakes, reassess the science, and adjust suboptimal investments. The limiting element in this approach to adaptation is likely to be the availability of consistent, long-term financing. 相似文献
Consistent individual differences in behavior, commonly termed animal personality, are a widespread phenomenon across taxa that have important consequences for fitness, natural selection, and trophic interactions. Animal personality research may prove useful in several conservation contexts, but which contexts remains to be determined. We conducted a structured literature review of 654 studies identified by combining search terms for animal personality and various conservation subfields. We scored the relevance of personality and conservation issues for each study to identify which studies meaningfully integrated the 2 fields as opposed to surface-level connections or vague allusions. We found a taxonomic bias toward mammals (29% of all studies). Very few amphibian or reptile studies applied personality research to conservation issues (6% each). Climate change (21%), invasive species (15%), and captive breeding and reintroduction (13%) were the most abundant conservation subfields that occurred in our search, though a substantial proportion of these papers weakly integrated conservation and animal personality (climate change 54%, invasive species 51%, captive breeding and reintroduction 40%). Based on our results, we recommend that researchers strive for consistent and broadly applicable terminology when describing consistent behavioral differences to minimize confusion and improve the searchability of research. We identify several gaps in the literature that appear to be promising and fruitful avenues for future research, such as disease transmission as a function of sociability or exploration as a driver of space use in protected areas. Practitioners can begin informing future conservation efforts with knowledge gained from animal personality research. 相似文献