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Agardy, T, Bridgewater P, Crosby MP, Day J, Dayton PK, Kenchington R, Laffoley D, McConney P, Murray PA, Parks JE, Peau L.  2003.  Dangerous targets? Unresolved issues and ideological clashes around marine protected areas Aquatic Conservation-Marine and Freshwater Ecosystems. 13:353-367.   10.1002/aqc.583   AbstractWebsite

1. While conservationists, resource managers, scientists and coastal planners have recognized the broad applicability of marine protected areas (MPAs), they are often implemented without a firm understanding of the conservation science - both ecological and socio-economic - underlying marine protection. The rush to implement MPAs has set the stage for paradoxical differences of opinions in the marine conservation community. 2. The enthusiastic prescription of simplistic solutions to marine conservation problems risks polarization of interests and ultimately threatens bona fide progress in marine conservation. The blanket assignment and advocacy of empirically unsubstantiated rules of thumb in marine protection creates potentially dangerous targets for conservation science. 3. Clarity of definition, systematic testing of assumptions, and adaptive application of diverse MPA management approaches are needed so that the appropriate mix of various management tools can be utilized, depending upon specific goals and conditions. Scientists have a professional and ethical duty to map out those paths that are most likely to lead to improved resource management and understanding of the natural world, including the human element, whether or not they are convenient, politically correct or publicly magnetic. 4. The use of MPAs as a vehicle for promoting long-term conservation and sustainable use of marine biodiversity is in need of focus, and both philosophical and applied tune ups. A new paradigm arising out of integrated, multi-disciplinary science, management and education/outreach efforts must be adopted to help promote flexible, diverse and effective MPA management strategies. Given scientific uncertainties, MPAs should be designed so one can learn from their application and adjust their management strategies as needed, in the true spirit of adaptive management. 5. It is critical for the conservation community to examine why honest differences of opinion regarding MPAs have emerged, and recognize that inflexible attitudes and positions are potentially dangerous. We therefore discuss several questions - heretofore taken as implicit assumptions: (a) what are MPAs, (b) what purpose do MPAs serve, (c) are no-take MPAs the only legitimate MPAs, (d) should a single closed area target be set for all MPAs, and (e) how should policymakers and conservation communities deal with scientific uncertainty? Copyright (C) 2003 John Wiley Sons, Ltd.

Riddle, MJ, Alongi DM, Dayton PK, Hansen JA, Klumpp DW.  1990.  Detrital pathways in a coral reef lagoon .1. macrofaunal biomass and estimates of production. Marine Biology. 104:109-118.   10.1007/bf01313164   AbstractWebsite

Coral reef lagoons are generally regarded as zones of net heterotrophy reliant on organic detritus generated in more productive parts of the reef system, such as the seaward reef flat. The abundance and biomass of sediment infauna were measured seasonally for one year (1986) within the lagoon of Davies Reef, central Great Barrier Reef, to test the hypothesis that macrofaunal biomass and production of coral reef lagoons would decrease with distance from the reef flat and would change seasonally. In general, there were no simple relationships between infaunal standing stock or production and distance from the reef flat or season. Bioturbation by callianassid shrimps negatively affected the abundance of smaller infauna, suggesting a community limited by biogenic disturbance rather than by supply of organic material. Polychaetes and crustaceans were dominant amongst the smaller infauna (0.5 to 2mm) while larger animals (> 2 mm) were mostly polychaetes and molluscs. Mean biomass of infauna at both sites and all seasons was 3 181 mg C m−2. The smaller animals (0.5 to 2 mm) contributed about 40% of total macrofaunal respiration and production although they represented only 15% of the total macrofaunal biomass. The biomass of macrofauna was about equal to that of the bacteria and meiofauna, while respiration represented 10 to 20% of total community respiration. Consumption by macrofauna accounts for only 3 to 11% of total organic inputs to sediment, with a further 14 to 17% being lost by macrofaunal respiration.

Hansen, JA, Klumpp DW, Alongi DM, Dayton PK, Riddle MJ.  1992.  Detrital pathways in a coral reef lagoon .2. detritus deposition, benthic microbial biomass and production. Marine Biology. 113:363-372.   10.1007/bf00349160   AbstractWebsite

Coral reef lagoons have generally been regarded as sinks for organic matter exported from more productive reef front and reef flat zones. The object of this study was to examine the importance of detritus as a carbon source for benthic communities in the lagoon at Davies Reef, central Great Barrier Reef. We report the results of seasonal measurements, taken in 1986, of bacterial numbers and production, protozoan numbers, community primary production and respiration in the sediments of Davies Reef lagoon. Deposition rates of organic matter in the lagoon were also measured. Deposition rates (+/- 1 SE) of carbon ranged from 9.2 (+/- 1.5) to 140.7 (+/- 10.3) mg Cm-2 d-1. Deposition rates were highest in winter and spring, lowest in summer. Rates of bacterial production ranged from 4.7 (+/- 0.2) pmol thymidine in-corporated g-1 dry wt (DW) h-1 in winter to 23.5 (+/- 1.0) pmol thymidine incorporated g-1 DW h-1 in spring. The number of ciliates ranged from 65 (+/- 10) to 356 (+/- 50) cm-3 through the year and the number of large (greater-than-or-equal-20-mu-m) flagellates from 38 (+/- 7) to 108 (+/- 16) There were no clear relationships between the sediment organic content, detrital input or temperature and the rates of bacterial processes, community metabolism or the standing stocks of microbes in the lagoon. The relative significance of detritus and in situ primary production as sources of carbon in the lagoon varied with season. In summer and autumn, detritus was less important than primary production as a source of carbon (4 to 27% of total carbon input). In winter and spring, detritus input became more significant in supply of carbon to the sediments (32 to 67% of the total carbon input). The lagoon does not simply act as a sink for carbon exported from the reef flat. We calculate that only 5% of the net reef flat primary production reached lagoon sediments in summer, but nearly 40% in winter.

Auster, PJ, Fujita R, Kellert SR, Avise J, Campagna C, Cuker B, Dayton P, Heneman B, Kenchington R, Stone G, Di Sciara GN, Glynn P.  2009.  Developing an ocean ethic: science, utility, aesthetics, self-interest, and different ways of knowing. Conservation Biology. 23:233-235.   10.1111/j.1523-1739.2008.01057.x   AbstractWebsite
Parnell, PE, Groce AK, Stebbins TD, Dayton PK.  2008.  Discriminating sources of PCB contamination in fish on the coastal shelf off San Diego, California (USA). Marine Pollution Bulletin. 56:1992-2002.   10.1016/j.marpolbul.2008.08.023   AbstractWebsite

Management of coastal ecosystems necessitates the evaluation of pollutant loading based on adequate source discrimination. Monitoring of sediments and fish on the shelf off San Diego has shown that some areas on the shelf are contaminated with polychlorinated biphenyls (PCBs). Here, we present an analysis of PCB contamination in fish on the shelf off San Diego designed to discriminate possible sources. The analysis was complicated by the variability of species available for analysis across the shelf, variable affinities of PCBs among species, and non-detects in the data. We utilized survival regression analysis to account for these complications. We also examined spatial patterns of PCBs in bay and offshore sediments and reviewed more than 20 years of influent and effluent data for local wastewater treatment facilities. We conclude that most PCB contamination in shelf sediments and fish is due to the ongoing practice of dumping contaminated sediments dredged from San Diego Bay. (C) 2008 Elsevier Ltd. All rights reserved.

Dayton, PK, Watson D, Palmisano A, Barry JP, Oliver JS, Rivera D.  1986.  Distribution patterns of benthic microalgal standing stock at Mcmurdo Sound, Antarctica. Polar Biology. 6:207-213.   10.1007/bf00443397   AbstractWebsite

During the austral summer of 1975–76 and winter of 1977 benthic and water column chlorophyll a and phaeopigments were measured at several sites along the east and west sides of McMurdo Sound, Antarctica. Estimates of in situ primary productivity were made at some McMurdo Sound locations. Additionally, water column samples were collected at 5 stations in the Ross Sea during January, 1976. Standing stock data are analyzed to identify seasonal and spatial patterns. Variability in algal standing stock was related to ambient light levels and appeared to be mediated by ice and snow cover whereby the highest algal standing stock was present under high light conditions (low ice and snow cover, shallow water, summer). Differences in published benthic invertebrate densities appear to be closely allied to differences in benthic primary production, and less so to in situ planktonic ice microalgal production.

Thrush, SF, Hewitt JE, Cummings VJ, Dayton PK, Cryer M, Turner SJ, Funnell GA, Budd RG, Milburn CJ, Wilkinson MR.  1998.  Disturbance of the marine benthic habitat by commercial fishing: Impacts at the scale of the fishery. Ecological Applications. 8:866-879.   10.1890/1051-0761(1998)008[0866:dotmbh];2   AbstractWebsite

Commercial fishing is one of the most important human impacts on the marine benthic environment. One such impact is through disturbance to benthic habitats as fishing gear (trawls and dredges) are dragged across the seafloor. While the direct effects of such an impact on benthic communities appear obvious, the magnitude of the effects has been very difficult to evaluate. Experimental fishing-disturbance studies have demonstrated changes in small areas; however, the broader scale implications attributing these changes to fishing impacts are based on long-term data and have been considered equivocal. By testing a series of a priori predictions derived from the literature (mainly results of small-scale experiments), we attempted to identify changes in benthic communities at the regional scale that could be attributed to commercial fishing. Samples along a putative gradient of fishing pressure were collected from 18 sites in the Hauraki Gulf, New Zealand. These sites varied in water depth from similar to 17 to 35 m and in sediment characteristics from similar to 1 to 48% mud and from 3 to 8.5 mu g chlorophyll alpha/cm(3). Video transects were used for counting large epifauna and grab/suction dredge and core sampling were used for collecting macrofauna. After accounting for the effects of location and sediment characteristics, 15-20% of the variability in the macrofauna community composition sampled in the cores and grab/suction dredge samples was attributed to fishing. With decreasing fishing pressure we observed increases in the density of echinoderms, long-lived surface dwellers, total number of species and individuals, and the Shannon-Weiner diversity index. In addition, there were decreases in the density of deposit feeders, small opportunists, and the ratio of small to large individuals of the infaunal heart urchin, Echinocardium australe. The effects of fishing on the larger macrofauna collected from the grab/suction dredge samples were not as clear. However, changes in the predicted direction in epifaunal density and the total number of individuals were demonstrated. As predicted, decreased fishing pressure significantly increased the density of large epifauna observed in video transects. Our data provide evidence of broad-scale changes in benthic communities that can be directly related to fishing. As these changes were identifiable over broad spatial scales they are likely to have important ramifications for ecosystem management and the development of sustainable fisheries.

Thrush, SF, Dayton PK.  2002.  Disturbance to marine benthic habitats by trawling and dredging: Implications for marine biodiversity. Annual Review of Ecology and Systematics. 33:449-473.   10.1146/annurev.ecolysis.33.010802.150515   AbstractWebsite

The direct effects of marine habitat disturbance by commercial fishing have been well documented. However, the potential ramifications to the ecological function of seafloor communities and ecosystems have yet to be considered. Softsediment organisms create much of their habitat's structure and also have crucial roles in many population, community, and ecosystem processes. Many of these roles are filled by species that are sensitive to habitat disturbance. Functional extinction refers to the situation in which species become so rare that they do not fulfill the ecosystem roles that have evolved in the system. This loss to the ecosystem occurs when there are restrictions in the size, density, and distribution of organisms that threaten the biodiversity, resilience, or provision of ecosystem services. Once the functionally important components of an ecosystem are missing, it is extremely difficult to identify and understand ecological thresholds. The extent and intensity of human disturbance to oceanic ecosystems is a significant threat to both structural and functional biodiversity and in many cases this has virtually eliminated natural systems that might serve as baselines to evaluate these impacts.