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1.

Background

Environmental impacts of human activities on the deep seafloor are of increasing concern. While activities within waters shallower than 200 m have been the focus of previous assessments of anthropogenic impacts, no study has quantified the extent of individual activities or determined the relative severity of each type of impact in the deep sea.

Methodology

The OSPAR maritime area of the North East Atlantic was chosen for the study because it is considered to be one of the most heavily impacted by human activities. In addition, it was assumed data would be accessible and comprehensive. Using the available data we map and estimate the spatial extent of five major human activities in the North East Atlantic that impact the deep seafloor: submarine communication cables, marine scientific research, oil and gas industry, bottom trawling and the historical dumping of radioactive waste, munitions and chemical weapons. It was not possible to map military activities. The extent of each activity has been quantified for a single year, 2005.

Principal Findings

Human activities on the deep seafloor of the OSPAR area of the North Atlantic are significant but their footprints vary. Some activities have an immediate impact after which seafloor communities could re-establish, while others can continue to make an impact for many years and the impact could extend far beyond the physical disturbance. The spatial extent of waste disposal, telecommunication cables, the hydrocarbon industry and marine research activities is relatively small. The extent of bottom trawling is very significant and, even on the lowest possible estimates, is an order of magnitude greater than the total extent of all the other activities.

Conclusions/Significance

To meet future ecosystem-based management and governance objectives for the deep sea significant improvements are required in data collection and availability as well as a greater awareness of the relative impact of each human activity.  相似文献   

2.
Pacific herring (Clupea pallasi) are an abundant and important component of the coastal ecosystems for the west coast of North America. Current Canadian federal herring management assumes five regional herring populations in British Columbia with a high degree of exchange between units, and few distinct local populations within them. Indigenous traditional knowledge and historic sources, however, suggest that locally adapted, distinct regional herring populations may have been more prevalent in the past. Within the last century, the combined effects of commercial fishing and other anthropogenic factors have resulted in severe declines of herring populations, with contemporary populations potentially reflecting only the remnants of a previously more abundant and genetically diverse metapopulation. Through the analysis of 85 archaeological herring bones, this study attempted to reconstruct the genetic diversity and population structure of ancient herring populations using three different marker systems (mitochondrial DNA (mtDNA), microsatellites and SNPs). A high success rate (91%) of DNA recovery was obtained from the extremely small herring bone samples (often <10 mg). The ancient herring mtDNA revealed high haplotype diversity comparable to modern populations, although population discrimination was not possible due to the limited power of the mtDNA marker. Ancient microsatellite diversity was also similar to modern samples, but the data quality was compromised by large allele drop-out and stuttering. In contrast, SNPs were found to have low error rates with no evidence for deviations from Hardy-Weinberg equilibrium, and simulations indicated high power to detect genetic differentiation if loci under selection are used. This study demonstrates that SNPs may be the most effective and feasible approach to survey genetic population structure in ancient remains, and further efforts should be made to screen for high differentiation markers.This study provides the much needed foundation for wider scale studies on temporal genetic variation in herring, with important implications for herring fisheries management, Aboriginal title rights and herring conservation.  相似文献   

3.
Bottlenose dolphin stock structure in the northeast Atlantic remains poorly understood. However, fine scale photo-id data have shown that populations can comprise multiple overlapping social communities. These social communities form structural elements of bottlenose dolphin (Tursiops truncatus) populations, reflecting specific ecological and behavioural adaptations to local habitats. We investigated the social structure of bottlenose dolphins in the waters of northwest Ireland and present evidence for distinct inshore and offshore social communities. Individuals of the inshore community had a coastal distribution restricted to waters within 3 km from shore. These animals exhibited a cohesive, fission-fusion social organisation, with repeated resightings within the research area, within a larger coastal home range. The offshore community comprised one or more distinct groups, found significantly further offshore (>4 km) than the inshore animals. In addition, dorsal fin scarring patterns differed significantly between inshore and offshore communities with individuals of the offshore community having more distinctly marked dorsal fins. Specifically, almost half of the individuals in the offshore community (48%) had characteristic stereotyped damage to the tip of the dorsal fin, rarely recorded in the inshore community (7%). We propose that this characteristic is likely due to interactions with pelagic fisheries. Social segregation and scarring differences found here indicate that the distinct communities are likely to be spatially and behaviourally segregated. Together with recent genetic evidence of distinct offshore and coastal population structures, this provides evidence for bottlenose dolphin inshore/offshore community differentiation in the northeast Atlantic. We recommend that social communities should be considered as fundamental units for the management and conservation of bottlenose dolphins and their habitat specialisations.  相似文献   

4.
5.
Ophidion lozanoi n.sp. is characterized by four rakers in the lower limb of the first gill arch; a large rostra1 spine; 24–26 pectoral rays; four rows of palatine teeth, and body squamation beginning at the occiput.  相似文献   

6.
Atmospheric deposition of nutrients to the North Atlantic Basin   总被引:12,自引:6,他引:12  
Atmospheric chemical models are used to estimate the deposition rate of various inorganic oxides of nitrogen (NOy), reduced nitrogen species (NHx) and mineral dust to the North Atlantic Ocean (NAO). The estimated deposition of NOy to the NAO (excluding the coastal ocean) and the Caribbean is 360 × 109 Moles-N m–2 yr–1 (5.0 Tg N); this is equivalent to about 13% of the estimated global emission rate (natural and anthropogenic) and a quarter of the emission rate from sources in North America and Europe. In the case of NHx, 258 Moles-N m–2 yr–1 (3.6 Tg N) are deposited to the NAO and the Caribbean; this is about 6% of the global continental emissions. There is relatively little data on the deposition rate of organic nitrogen species; nonetheless, this evidence suggests that concentrations and deposition rates are comparable to those for inorganic nitrogen.Because of anthropogenic emissions, the present-day deposition rate of NOy to the NAO is about five times greater than pre-industrial times largely due to emissions from energy production and biomass burning. The present-day emissions of NHx from continental anthropogenic sources are about four-to-five times greater than natural sources, mostly due to the impact of emissions from animal wastes associated with food production. Indeed, present-day emissions of NHx from animal waste are estimated to be about 10 times greater than the pre-human era. The deposition rate of mineral dust to the NAO is about 170 Tg yr–1; deposited with the dust (assuming average crustal abundances) is about 6 Tg yr–1 of Fe and 0.2 Tg yr–1 of P. Dust deposition in the NAO is almost completely attributable to transport from North African sources; a substantial fraction of the dust over the NAO is probably mobilized as a consequence of land use practices in arid regions and, consequently, it should be regarded as a pollutant.  相似文献   

7.
North winds and production in the eastern North Atlantic   总被引:9,自引:0,他引:9  
A long-term increase in northerly wind componentl over the easternNorth Atlantic and European Seaboard between 1950 and 1980 isassociated both with a decline of phytoplankton and zooplanktonbiomass in sea-areas around the British Isles, and with an increasein upwelling intensity along the Iberian west coast. The implicationsfor certain pelagic fish stocks in the area are assessed.  相似文献   

8.
We examined polymorphism at 12 microsatelliteloci in 807 harbour porpoises , Phocoenaphocoena, collected from throughout thecentral and eastern North Atlantic to theBaltic Sea. Multilocus tests for allelefrequency differences, assignment tests,population structure estimates (FST) andgenetic distance measures (DLR andDC) all indicate six geneticallydifferentiated populations/sub-populationsafter pooling sub-samples within regions.Harbour porpoises from West Greenland, theNorwegian Westcoast, Ireland, the British NorthSea, the Danish North Sea and the inland watersof Denmark (IDW) are all geneticallydistinguishable from each other. A sample ofharbour porpoises collected off the Dutch coast(mainly during winter) was geneticallyheterogeneous and likely comprised a mixture ofindividuals of diverse origin. A mixed stockanalysis indicated that most of the individualsin this sample (77%) were likely migrantsfrom the British and Danish North Sea.  相似文献   

9.
Earth has experienced five major extinction events in the past 450 million years. Many scientists suggest we are now witnessing a sixth, driven by human impacts. However, it has been difficult to quantify the real extent of the current extinction episode, either for a given taxonomic group at the continental scale or for the worldwide biota, largely because comparisons of pre-anthropogenic and anthropogenic biodiversity baselines have been unavailable. Here, we compute those baselines for mammals of temperate North America, using a sampling-standardized rich fossil record to reconstruct species-area relationships for a series of time slices ranging from 30 million to 500 years ago. We show that shortly after humans first arrived in North America, mammalian diversity dropped to become at least 15%–42% too low compared to the “normal” diversity baseline that had existed for millions of years. While the Holocene reduction in North American mammal diversity has long been recognized qualitatively, our results provide a quantitative measure that clarifies how significant the diversity reduction actually was. If mass extinctions are defined as loss of at least 75% of species on a global scale, our data suggest that North American mammals had already progressed one-fifth to more than halfway (depending on biogeographic province) towards that benchmark, even before industrialized society began to affect them. Data currently are not available to make similar quantitative estimates for other continents, but qualitative declines in Holocene mammal diversity are also widely recognized in South America, Eurasia, and Australia. Extending our methodology to mammals in these areas, as well as to other taxa where possible, would provide a reasonable way to assess the magnitude of global extinction, the biodiversity impact of extinctions of currently threatened species, and the efficacy of conservation efforts into the future.  相似文献   

10.
Body condition is an indicator of health, and it plays a key role in many vital processes for mammalian species. While evidence of individual body condition can be obtained, these observations provide just brief glimpses into the health state of the animal. An analytical framework is needed for understanding how health of animals changes over space and time.Through knowledge of individual health we can better understand the status of populations. This is particularly important in endangered species, where the consequences of disruption of critical biological functions can push groups of animals rapidly toward extinction. Here we built a state-space model that provides estimates of movement, health, and survival. We assimilated 30+ years of photographic evidence of body condition and three additional visual health parameters in individual North Atlantic right whales, together with survey data, to infer the true health status as it changes over space and time. We also included the effect of reproductive status and entanglement status on health. At the population level, we estimated differential movement patterns in males and females. At the individual level, we estimated the likely animal locations each month. We estimated the relationship between observed and latent health status. Observations of body condition, skin condition, cyamid infestation on the blowholes, and rake marks all provided measures of the true underlying health. The resulting time series of individual health highlight both normal variations in health status and how anthropogenic stressors can affect the health and, ultimately, the survival of individuals. This modeling approach provides information for monitoring of health in right whales, as well as a framework for integrating observational data at the level of individuals up through the health status of the population. This framework can be broadly applied to a variety of systems – terrestrial and marine – where sporadic observations of individuals exist.  相似文献   

11.
The study comprises a data set of CTD, optical properties—K 0(PAR), c p, a(PAR), b(PAR)—and optical constituents—Chl a, SPM, CDOM—from 72 shelf and off-shelf stations in the Faroe Islands (62°N, 7°W) North East Atlantic, in early spring 2005. Results showed that shelf waters surrounding the islands were cold and low saline, whereas off-shelf waters were warmer (~1°C) and more saline (~0.05) PSU. A pronounced oceanographic front separated the two waters, and diffuse light attenuation K 0(PAR), beam attenuation c p, Chl a, absorption a(PAR), and scattering coefficient b(PAR) were all significantly higher on the shelf. Analyses showed that off-shelf light attenuation K 0(PAR) was governed by Chl a, shown by a high (r 2 = 0.64) Chl aK 0(PAR) correlation, whereas light attenuation on the shelf was governed by both Chl a, SPM, and CDOM in combination. A Chl a specific diffuse attenuation coefficient K0* ( textPAR ) K_{0}^{*} left( {text{PAR}} right) of 0.056 (m2 mg−1 Chl a) and a Chl a specific beam attenuation ( ctextp* c_{text{p}}^{*} ) of 0.27 (m2 mg−1 Chl a) coefficients were derived for the off-shelf. It is pointed out that Chl a is the single variable that changes over time as no rivers with high SPM and CDOM enter the shelf area. Data were obtained in early spring, and Chl a concentrations were low ~0.5 mg Chl a m−3. Spring bloom Chl a are about 10 mg Chl a m−3 and estimations showed that shelf K 0(PAR) will increase about 5 times and beam attenuation about 10 times. The Faroe Islands shelf–off-shelf waters is a clear example where physical conditions maintain some clear differences in optical properties and optical constituents. The complete data set is enclosed.  相似文献   

12.
The recent introduction of the macroalgaUndaria pinnatifida (Harvey) Suringar into the North Atlantic is the latest of a large number of introductions, which have occurred over many years. Some have been deliberate introductions for mariculture or research, while most have been accidental, via vectors such as shipping and shellfish imports. Not all newly recorded species are introductions; some are thought to be merely extensions of distribution, e.g.Laminaria ochroleuca, while others may have been overlooked previously, e.g.Scytosiphon dotyi. Subsequent to its accidental introduction into the waters around the Mediterranean French coast at Sete, most likely with imported oysters,Undaria was deliberately introduced into the North Atlantic, to Brittany, in 1983 by IFREMER for commercial exploitation.Undaria has since spread from the original sites in Brittany, and is now established at several sites on the south coast of England. This paper discusses the introduced brown algae in the North Atlantic and outlines the establishment ofUndaria in the UK.  相似文献   

13.
14.
Common Terns nesting at Bermuda are isolated by 1,000–4,000?km from other populations of the species around the North Atlantic Ocean. This population experienced a severe demographic bottleneck as a result of a hurricane in 2003 and was subsequently re-established by four males and four females. Using seven microsatellite loci, we compared the genetic diversity of the pre- and post-bottleneck populations, compared the genetic profile of the Bermuda population with those of other populations around the North Atlantic Ocean and mainland Europe, and assessed the potential contribution of immigration to genetic diversity. We found a loss of genetic diversity (number of alleles and heterozygosity) in the post-bottleneck Bermudian population (4.6–2.9 and 0.56–0.52, respectively). We also report significant differentiation among all sampled locations (global FST?=?0.16) with no evidence for immigration into Bermuda. Common Terns from the Azores were genetically more similar to those from mainland North America than to those from Bermuda or mainland Europe. Our results suggest that the critically endangered population in Bermuda is genetically distinct and requires continued and enhanced conservation priority.  相似文献   

15.
Nine bottlenose dolphin (Tursiops truncatus) calves that stranded in Virginia in 1996 and 1997 died of severe blunt-force trauma. Injuries were concentrated on the head and chest and multiple rib fractures, lung lacerations, and soft tissue contusions were prominent. Skeletal and/or soft tissue trauma occurred bilaterally in all of the calves. One had a bite wound across the left mandible that exhibited deep punctures consistent with the tooth placement in an adult bottlenose dolphin. The lesions were not compatible with predation, boat strike, fisheries interactions, rough-surf injury, or blast injury. However, they were similar to traumatic injuries described in stranded bottlenose dolphin calves and harbor porpoises (Phocoena phocoena) in Great Britain attributed to violent dolphin interactions. The evidence suggests that violent dolphin behavior was the cause of the trauma in the nine calves reported here and that infanticide occurs in bottlenose dolphins of the western North Atlantic.  相似文献   

16.
Marine Crenarchaeota are among the most abundant groups of prokaryotes in the ocean and recent reports suggest that they oxidize ammonia as an energy source and inorganic carbon as carbon source, while other studies indicate that Crenarchaeota use organic carbon and hence, live heterotrophically. We used catalysed reporter deposition fluorescence in situ hybridization (CARD‐FISH) to determine the crenarchaeal and bacterial contribution to total prokaryotic abundance in the (sub)tropical Atlantic. Bacteria contributed ~50% to total prokaryotes throughout the water column. Marine Crenarchaeota Group I (MCGI) accounted for ~5% of the prokaryotes in subsurface waters (100 m depth) and between 10 and 20% in the oxygen minimum layer (250–500 m depth) and deep waters (North East Atlantic Deep Water). The fraction of both MCGI and Bacteria fixing inorganic carbon, determined by combining microautoradiography with CARD‐FISH (MICRO‐CARD‐FISH), decreased with depth, ranging from ~30% in the oxygen minimum zone to < 10% in the intermediate waters (Mediterranean Sea Outflow Water, Antarctic Intermediate Water). In the deeper water masses, however, MCGI were not taking up inorganic carbon. Using quantitative MICRO‐CARD‐FISH to determine autotrophy activity on a single cell level revealed that MCGI are incorporating inorganic carbon (0.002–0.1 fmol C cell?1 day?1) at a significantly lower rate than Bacteria (0.01–0.6 fmol C cell?1 day?1). Hence, it appears that MCGI contribute substantially less to autotrophy than Bacteria. Taking the stoichiometry of nitrification together with our findings suggests that MCGI might not dominate the ammonia oxidation step in the mesopelagic waters of the ocean to that extent as the reported dominance of archaeal over bacterial amoA would suggest.  相似文献   

17.
In the present study, we examined the divergence time and the magnitude of gene flow between two distantly separated populations of North Pacific light fish Maurolicus japonicus, one in the southern part of the East Sea (off Korea) and the other in the Southeast Atlantic Ocean (off Namibia). The mitochondrial 16SrDNA sequences (524 base pairs) obtained from the two populations were analyzed using the isolation with migration (IM) coalescent method as well as the conventional F ST statistic and a phylogeographic method. A significant nonzero F ST value (0.176, P<0.05) indicated genetic differentiation between the two populations. The low level of nucleotide diversity compared to the moderately high level of haplotype diversity implied that the populations have experienced a bottleneck followed by rapid growth in both populations. IM analysis suggested that these two populations most likely split approximately 500?C800 K years ago during the Pleistocene climatic oscillations and that gene flow has occurred unidirectionally from the Southeast Atlantic population to the East Sea population. Nested clade phylogeographic analysis supports restricted gene flow between the two populations.  相似文献   

18.
SuperTRI是Ropiquet等(2009)发表的一种新的超树方法,可以通过合并所有系统发育信息来共同组建大的系统发育树.该方法克服了超矩阵法和传统超树法的一些限制,使提出的系统发育假说可信度更高,更具有统计说服力.本文应用SupperTRI方法重建了百合目(Liliales)主要类群的系统发育关系,并与超矩阵法的分析结果进行了比较.结果显示:(1) SuperTRI方法产生了与超矩阵法相似的拓扑结构,但节点支持率相对较低,其中再现性指数对评判分支的可信性更容易理解,在系统树图示方法上也更直观;(2)SuperTRI系统树证实百合科、菝葜科、垂花科和菝葜藤科为一单系分支;黑药花科为一独立分支;秋水仙科、六出花科、刺藤科为一单系分支,但这3个大分支间的关系未明;支持白玉簪科和金梅草科互为姐妹群,是百合目最基部类群.  相似文献   

19.
The suggested strategies for a screening programme for Down''s syndrome by maternal serum alpha fetoprotein concentration were examined and tested on the experience of the North East Thames Regional. Screening by maternal serum alpha fetoprotein concentration may be used to identify pregnancies at increased risk, but this is useful only in women aged over 32 whose collective risk is greater than one in 200. The absolute probability of carrying babies with Down''s syndrome for individuals in this high risk group can then be calculated and used to decide whether further diagnosis by amniocentesis is desired.  相似文献   

20.
The distribution of a number of Mesozoic brachiopods indicates a migration up the eastern side of the North Atlantic starting in the early Jurassic and reaching as far north as Greenland by the beginning of Cretaceous times. The brachiopods evidently reached the new Atlantic via the Rif mountains of northern Morocco and migrated both north and south from there. Some of them came from the central High Atlas which represents a gulf open to the east but closed to the west. The western High Atlas, on the other hand, was populated by successive waves of forms from the west. Brachiopods and other distinctive forms of “Tethyan” origin clearly extended considerably farther north on the eastern side of the Atlantic than they did on the west. This probably implies an early establishment of the Gulf Stream. Some Tethyan brachiopods which did not extend to the western end of the Mediterranean are found instead to have spread via northeast Siberia to cordilleran North America.  相似文献   

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