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The role of isolated mountain forests in Central Asian drylands has been the subject of a number of recent studies. The present paper examines islands of birch and willow forest in the Mongolian Govi Altay Mountains. Using vegetation surveys, dendrochronological studies and charcoal findings, it is attempted to assess the present-day ecological state of the vegetation as well as the environmental history and ecological trends. One of the three forests studied seems to be expanding rapidly due to declining levels of utilization under climatically favourable conditions. The other forests however, situated about 350 km to the south-east of the former, are threatened by consistently high levels of anthropogenic pressure. Based on ecological evidence, the forest islands’ role as witnesses of a once coherent forest belt that may have been retreating since the mid-Holocene is discussed. [ABSTRACT FROM AUTHOR]

In the 20th century, the global climate has warmed about 0.6 K. High-mountain areas as well as areas of high latitudes are experiencing even greater increases in temperature especially in the last half century. With changing climatic conditions, the determinants of global, and in particular, altitudinal distribution of plants and plant communities are likely to change and a subsequent reaction of climate sensitive species and ecosystems is expected. The following paper focuses on observed climate-induced changes in the two uppermost altitudinal vegetational ecotones at the treeline and the upper limit of plant life at the alpine-nival transition zone. [ABSTRACT FROM AUTHOR]

Based on comprehensive evaluations and analyses of existing literature and data sources, a review of geographical and ecological aspects of the upper timberline in the Himalayan mountain system is presented. Upper timberline elevations increase along two gradients: a NW-SE gradient corresponds to higher temperature sums at same elevations along the mountain arc. However, mean temperatures of the warmest month are higher at timberlines in the NW, which develop at lower elevations than expected since extreme winter cold, later snow melt, and shorter growing seasons overcompensate the advantage of higher summer temperatures. A second gradient is developed in peripheral-central direction from the Himalayan south slope to the Great Himalayan range and the Tibetan highlands. Increasing timberline elevations along this gradient are related to the combined effects of continentality and mass-elevation, both leading to higher temperature sums. Juniperus tibetica stands in S-Central Tibet even reach 4600–4800 m, the most elevated timberline in the northern hemisphere. Potentially natural timberline elevations are higher at south-facing slopes compared to north-facing slopes. The difference in altitudinal position is up to several hundred meters. The pronounced effects of exposure to solar radiation result in a much higher utilization pressure at sunny slopes, in particular with regard to pastoral use. South-facing slopes have since long been subjected to massive human impacts throughout the mountain arc so that natural conditions are hard to reconstruct. The depression of upper timberline may amount to more than 500 m, largely depending on the local/ regional utilization potential of alpine pasture areas. With regard to physiognomy, high coniferous forests give way to medium-sized broadleaved tree stands and finally to a krummholz belt. This is the dominant timberline pattern on shady slopes, whereas remnant open coniferous forest stands on sunny slopes dissolve into isolated patches or single crippled trees higher up. Along the NW-SE gradient, north-facing slopes show a floristic change from deciduous Betula- to evergreen Rhododendron-dominated upper timberlines, which must be attributed to decreasing winter cold and strongly increasing humidity levels. Juniperus spp. are the principal timberline tree species on south-facing slopes throughout the mountain system. Relationships of Himalayan timberlines to other ecological conditions and processes such as carbon balance, freezing and frost drought, soil temperatures, wind, snow cover, soils, regeneration, etc., are still largely unexplored. The state of the art is summarized in this paper. More systematic, interdisciplinary timberline research in the Himalaya is strongly needed to better understand how complex ecological and socio-economic processes are expressed in present spatial and physiognomic timberline structures. [ABSTRACT FROM AUTHOR]

All species have limits to their distribution and individuals that demarcate margins demonstrate an end-point in adaptation to a changing environment. Limits to plant survival arise either from a failure to grow or from an inability to reproduce. Consequently, matching climatic data with geographical distribution has to consider the biological causes for the failure of plants to survive outside any given area. Physical factors, such as thermal time (day-degrees) and growing season length, differentiate between the broadly recognised vegetation zones of High, Low, and Subarctic. However, within these zones the limitations to plant distribution are less readily related to climatic factors. In peripheral areas, relating physical climatic factors to species occurrence requires a knowledge of the many interactions between physiology and genetics of populations as they approach their territorial margins. Examination of the extent of variation found in plants growing in cold habitats reveals large differences both between and within populations and at different seasons in metabolic rates, temperature responsiveness and metabolic efficiency. The High Arctic represents a peripheral zone where conditions are prone to large fluctuations. Consequently, plant distribution will be affected by aspects of the environment that are not permanent, but which occur irregularly with varying frequency and intensity. This paper considers the physiological and genetic properties of polar plant populations that may facilitate persistence in uncertain and heterogeneous adverse environments. Particular attention is given to those species that appear to have maintained a presence at high latitudes since pre-Pleistocene times and have therefore survived many past environmental fluctuations. [ABSTRACT FROM AUTHOR]

As awareness of deep-sea corals increases, global efforts to conserve them are increasing as well. Oceana, a non-governmental conservation organization that merged with the American Oceans Campaign in 2002, is focusing significant attention and resources on the conservation of deep-sea coral communities in United States’ waters. Oceana is carrying out a number of activities as part of its deep-sea coral campaign. These include: • Working to pass legislation that would ban the use of particularly destructive bottom trawls in all U.S. waters in collaboration with the Marine Conservation Biology Institute;• Working to pass legislation that would specifically protect known deep-sea coral and sponge areas and establish a process for future protections;• Working to protect deep-sea coral and sponge habitats in the U.S. through the regional fishery management councils;• Developing educational materials for decision-makers, the media, and the general public;• Developing a petition to achieve threatened or endangered species status for Oculina varicosa. The goal of Oceana’s deep-sea coral protection activities is to ban bottom trawling in all U.S. waters containing significant amounts of deep-sea corals and sponges by the end of 2006. The purpose of this paper is to discuss the activities that Oceana is engaged in to achieve this goal. As Oceana’s capacity develops in other parts of the world, its efforts to protect coral in other regions (especially Europe and South America) will increase as well. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the spatial distribution and morphology of coral banks in the Porcupine Seabight in relation to their environmental settings. The study area is characterised by well-delimited clusters of coral banks, each featuring typical bank morphology and environmental setting. In the central part of the basin, two mound provinces can be identified: a set of complex fl at topped seafloor mounds in the Hovland Mound province is flanked to the north by a crescent of numerous north-south elongated buried coral banks in the Magellan Mound province, along the eastern margin of the basin partly buried and seabed coral banks represent the Belgica Mound province. The banks are mound-shaped elevations, many of them hosting living deep-water corals (Lophelia pertusa, Madrepora oculata, Desmophyllum cristagalli, Dendrophyllia sp.) and associated fauna. This active biological layer covers a dead assemblage of corals clogged with mud. All coral banks, buried or seabed, occur in association with current-induced features (e.g., scouring features, dunes) and steep palaeo- and present-seabed slopes. Only a few banks have a present-day seabed expression, which suggests that environmental conditions have been more favourable for bank development in the past. The depth range of the seabed coral banks coincides with the Mediterranean Outflow Water which may control indirectly the coral distribution. The distribution of corals in the southern part of the North Atlantic and the actual link with Mediterranean water suggest a possible migration of corals within the Mediterranean water along the NE Atlantic margin. The start-up phase of the coral bank development in the basin has taken place simultaneously for all provinces, and tentatively framed in times subsequent to a Late Pliocene period of erosion and non-deposition. It is considered that the sedimentary load of the currents plays an important role in the bank development. Coral banks accrete by the active baffling of sediment by the biological framework and growth of the biological cap. When sedimentation and biological growth get out of balance, the framework will progressively be clogged with sediment. Once sediment dominates the structure the coral banks get buried and draped by sediment. [ABSTRACT FROM AUTHOR]

This paper describes the associated fauna of the deep-sea gorgonian corals Paragorgia arborea and Primnoa resedaeformis. Composition and distribution of this fauna is described based on material from the continental shelf and slope off Atlantic Canada (300–600 m depth). Samples were collected from five areas with Remotely Operated Vehicle, video grab, and bottom trawl. The collected material consists of 25 samples, 13 from P. arborea and 12 from P. resedaeformis. A total of 114 species and 3915 individuals were recorded. The P. resedaeformis fauna was more abundant and diverse than the fauna of P. arborea, with 2651 specimens and 97 species found on the former and 1264 specimens and 47 species on the latter. Rarefaction analysis indicated that many more associated species are still to be found. Species richness and abundance was significantly correlated with coral morphology (e.g., number of branches, wet weight, and % exposed skeleton). Crustaceans dominated the fauna, contributing 46 % to the total number of individuals and 26 % to the total number of species. Two coral microhabitats were identified: 1) young and live parts of colonies and, 2) old parts with deposits and exposed skeleton. Most of the associated fauna was found in the latter habitat. There was a clear difference in fauna composition of the two coral species. Sessile hydroids, anemones, and molluscs were more abundant on P. resedaeformis. These organisms occurred attached to the hard substratum provided by the exposed skeleton. Parasitic copepods and polychaetes were more common on P. arborea. Two copepods, a lichomolgid ecto-parasite and a lamippid gall-forming endoparasite, were associated with P. arborea. The echinoderm Gorgonocephaluslamarckii was found in the high current environment on the outer branches of P. arborea. The shrimp Pandalus propinquus was hiding and resting on colonies of both coral species. Many of the associated taxa are also found on tropical gorgonians but the deepsea gorgonians lack the diverse decapod and gastropod-fauna of their tropical counterparts. The species richness of the deep-sea gorgonian coral fauna was higher than what has been observed for tropical gorgonians. In contrast to the tropical associates very few are obligate symbionts. Nevertheless, several of the species are rare in other habitats and have been recorded on the same and other gorgonian species in early studies from the eastern North Atlantic. The sampling gear collected the fauna differently. Corals from bottom trawls had a poorer associated fauna that differed in composition with material collected by ROV or video assisted grab. [ABSTRACT FROM AUTHOR]

Deep-water Oculina coral reefs, which are similar in structure and development to deep-water Lophelia reefs, stretch 167 km (90 nm) at depths of 60–100 m along the eastern Florida shelf of the United States. These consist of numerous pinnacles and ridges, 3–35 m in height, that are capped with thickets of living and dead coral, Oculina varicosa. Extensive areas of dead Oculina rubble are due in part to human impacts (e.g., fish and shrimp trawling, scallop dredging, anchoring, bottom longlines, and depth charges) but also may be due in part to natural processes such as bioerosion, disease, or global warming. In the 1970s, the reefs were teeming with fish. By the early 1990s, both commercial and recreational fisheries had taken a toll on the reefs, especially on the coral habitat and populations of grouper and snapper. In 1984, 315 km2 (92 nm2) was designated the Oculina Habitat of Particular Concern (OHAPC), prohibiting trawling, dredging, bottom longlines and anchoring, and establishing the first deep-sea coral marine protected area in the world. In 2000, the Oculina Marine Protected Area (MPA) was expanded to 1029 km2 (300 nm2). Despite these protective measures, manned submersible and ROV observations in the Oculina MPA between 1995 and 2003 suggest that portions of the coral habitat have been reduced to rubble since the 1970s, grouper spawning aggregations may be absent, and illegal trawling continues. This paper is a review of the results of the mapping, habitat characterization, and fish surveys from the early historical studies (1960–1980s) to the more recent surveys (1995–2003). [ABSTRACT FROM AUTHOR]

The Belgica Mound province is one of three provinces where carbonate mounds are associated with cold-water coral species in Porcupine Seabight, west of Ireland. Building upon extensive existing datasets, the Polarstern ARK XIX/3a cruise, deploying the robotic submersible VICTOR6000 (ROV), was undertaken in June 2003. This paper presents an overview of preliminary results from a reconnaissance video survey over and between several steep-flanked Belgica Mounds (giant mounds) and from a microbathymetric survey over some smaller mounds (Moira Mounds). Visual evidence for a strong hydrodynamic regime in the vicinity of the carbonate mounds is found with the interaction between currents and sedimentation having an important role in mound growth and development. Only some mounds show a high percentage of live coral coverage although there is a clear increase of megafaunal concentrations and species on mounds. One area of the province (the eastern ridge of aligned mounds) revealed very little live coral cover, asymmetrical drift accumulations burying the eastern sides and sediment-clogged dead coral frameworks at the western sides. This is in contrast to other areas (e.g., the western alignment of mounds) that show abundant live coral cover at present. In nearly all parts of the survey area the impact of fisheries, especially demersal trawling, is noted. [ABSTRACT FROM AUTHOR]

One of the critical information needs identified at the 2003 Deep-Sea Corals Workshop in Galway, Ireland, was to locate and chart deep-sea corals in order to develop reliable estimates of their distribution and abundance. While reports of deep-sea corals from the Gulf of Mexico date back to the 1860s, relatively little is known about their distribution or abundance. This paper attempts to provide a current assessment of the occurrence of Lophelia pertusa and Madrepora oculata in water depths greater than 200 m in the Gulf of Mexico by summarizing records from (1) published material, (2) the 2003 National Museum of Natural History Taxonomic Database, (3) findings obtained during the September-October 2003 NOAA-OE RV Ronald H. Brown cruise RB-03-07-leg-2 in the northern Gulf, and (4) from various unpublished sources. [ABSTRACT FROM AUTHOR]

Climatic warming in northern latitudes will undoubtedly create new ecological opportunities for vegetation advance as ice sheets retreat and permanent snow cover is reduced. Depending on proximity to the oceans, and this includes the Arctic Ocean, the degree of winter versus summer warming is likely to differ. In northern regions the influence of oceanicity on plant distribution is very marked. The models described in this paper show that among some of the commonest woody species winter warming may in some cases cause a significant retreat in areas that where the climate is influenced by the ocean, while in other areas the species may make significant advances. Due to seasonal differentiation in responses to temperature the nature of the migration of species into these vacated areas or changing communities is unlikely to be a mere latitudinal shift northwards of existing species assemblages. It appears therefore highly probable that species migration will be strongly influenced by seasonality of temperature change, and for any one species similar patterns of climatic change in different parts of its range, could result in migration in opposite directions. Consequently, changing thermal conditions will be likely to alter species composition of existing northern plant communities. Attention will therefore have to be given to the roles of seasonality gradients as potential barriers to migration notwithstanding overall warming. [ABSTRACT FROM AUTHOR]

Over the years, viruses have been shown to be mortality agents for a wide range of phytoplankton species, including species within the genus Phaeocystis (Prymnesiophyceae). With its polymorphic life cycle, its worldwide distribution, and the capacity of several of the Phaeocystis species to form dense blooms, this genus is a key player for our understanding of biogeochemical cycling of elements. This paper provides an overview of what is know to date about the ecological role of viruses in regulating Phaeocystis population dynamics. It explores which variables affect the algal host-virus interactions, and examines the impact of virally induced cell lysis of Phaeocystis on the function and structure of the pelagic food web as well as on the flow of organic carbon and nutrients. [ABSTRACT FROM AUTHOR]

The phytoplankton genus Phaeocystis has well-documented, spatially and temporally extensive blooms of gelatinous colonies; these are associated with release of copious amounts of dimethyl sulphide (an important climate-cooling aerosol) and alterations of material flows among trophic levels and export from the upper ocean. A potentially salient property of the importance of Phaeocystis in the marine ecosystem is its physiological capability to transform between solitary cell and gelatinous colonial life cycle stages, a process that changes organism biovolume by 6-9 orders of magnitude, and which appears to be activated or stimulated under certain circumstances by chemical communication. Both life-cycle stages can exhibit rapid, phased ultradian growth. The colony skin apparently confers protection against, or at least reduces losses to, smaller zooplankton grazers and perhaps viruses. There are indications that Phaeocystis utilizes chemistry and/or changes in size as defenses against predation, and its ability to create refuges from biological attack is known to stabilize predator-prey dynamics in model systems. Thus the life cycle form in which it occurs, and particularly associated interactions with viruses, determines whether Phaeocystis production flows through the traditional "great fisheries" food chain, the more regenerative microbial food web, or is exported from the mixed layer of the ocean. Despite this plethora of information regarding the physiological ecology of Phaeocystis, fundamental interactions between life history traits and system ecology are poorly understood. Research summarized here, and described in the various papers in this special issue, derives from a central question: how do physical (light, temperature, particle distributions, hydrodynamics), chemical (nutrient resources, infochemistry, allelopathy), biological (grazers, viruses, bacteria, other phytoplankton), and self-organizational mechanisms (stability, indirect effects) interact with life-cycle transformations of Phaeocystis to mediate ecosystem patterns of trophic structure, biodiversity, and biogeochemical fluxes? Ultimately the goal is to understand and thus predict why Phaeocystis occurs when and where it does, and the bio-feedbacks between this keystone species and the multitrophic level ecosystem. [ABSTRACT FROM AUTHOR]

Recent national assessments document that nitrogen-driven coastal eutrophication is widespread and increasing in the United States. This significant coastal pollution problem includes impacts including increased areas and severity of hypoxic and anoxic waters; alteration of food webs; degradation and loss of sea grass beds, kelp beds and coral reefs; loss of biodiversity; and increased incidences and duration of harmful algal blooms. In this paper, we review two complementary approaches to assessing the causes and consequences of these trends, as well as potential remedies for them. The first is a national-scale assessment, drawn primarily from expert knowledge of those most familiar with the individual estuaries and integrated into a common analysis framework. The second approach, focused on the Mississippi/Atchafalaya basin — the largest US drainage basin — draws upon both quantitative and qualitative analyses within a comprehensive framework, Integrated Assessment. [ABSTRACT FROM AUTHOR]

Anthropogenic actions are altering fluxes of nitrogen (N) in the biosphere at unprecedented rates. Efforts to study these impacts have concentrated in the Northern hemisphere, where experimental data are available. In tropical developing countries, however, experimental studies are lacking. This paper summarizes available data and assesses the impacts of human activities on N fluxes in Puerto Rico, a densely populated Caribbean island that has experienced drastic landscape transformations over the last century associated with rapid socioeconomic changes. N yield calculations conducted in several watersheds of different anthropogenic influences revealed that disturbed watersheds export more N per unit area than undisturbed forested watersheds. Export of N from urban watersheds ranged from 4.8 kg ha−1 year−1 in the Rí o Bayamón watershed to 32.9 kg ha−1 year−1 in the highly urbanized Río Piedras watershed and 33.3 kg ha−1 year−1 in the rural-agricultural Río Grande de Añasco watershed. Along with land use, mean annual runoff explained most of the variance in fluvial N yield. Wastewater generated in the San Juan Metropolitan Area receives primary treatment before it is discharged into the Atlantic Ocean. These discharges are N-rich and export large amounts of N to the ocean at a rate of about 140 kg ha−1 year−1. Data on wet deposition of inorganic N (NH4+ + NO3−) suggest that rates of atmospheric N deposition are increasing in the pristine forests of Puerto Rico. Stationary and mobile sources of NOx (NO+NO2) and N2O generated in the large urban centers may be responsible for this trend. Comprehensive measurements are required in Puerto Rico to quantitatively characterize the local N cycle. More research is required to assess rates of atmospheric N deposition, N fixation in natural and human-dominated landscapes, N-balance associated with food and feed trade, and denitrification. [ABSTRACT FROM AUTHOR]

The alteration of the nitrogen (N) cycle by human activities is widespread and has often resulted in increased flows of nitrogen to the marine environment. In this paper we have attempted to know the changes of N fluxes in Cuba by quantifying the N inputs to the landscape from (1) fertilizer applications, (2) atmospheric deposition, (3) biological nitrogen fixation and (4) net import of food and feeds. N-inputs to the country progressively increased until the end of the 20th century, reaching a peak during the 80s when low cost fertilizer imported from the former Soviet Union led to heavy rates of application. This rapid growth represented more than a 5-fold increase with respect to pristine values; higher than the two-fold global increase of anthropogenic N reported by Vitousek et al. (1997 Human alteration of the global nitrogen cycle: sources and consequences. Ecol. Appl. 7:737-750). Inorganic fertilizer was the largest single source of reactive N, followed by atmospheric deposition, biological fixation, and net imports of foods and feed-stocks. Nitrogen inputs peaked in 1987 and data expressed on an area basis show that N flux to the Cuban landscape, in the 80s, was one of the highest reported in the literature. During the 90s, there was a dramatic drop in nitrogen inputs mainly associated to a decrease in the use of inorganic fertilizer. Other factors reducing nutrient inflows to Cuba, during the same period, were imports of foodstuff and livestock feeds, a decrease of nitrogen oxide emissions, and a decrease in the sugar cane crop area. Using an empirical relationship (Howarth et al. 1996 Regional nitrogen budgets and riverine N & O fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry 35:75-139) we present a very preliminary estimate of N-inputs to coastal waters and discuss the consequences of these changes on the coastal zone. [ABSTRACT FROM AUTHOR]

The production of reactive nitrogen worldwide has more than doubled in the last century because of human activities and population growth. Advances in our understanding of the nitrogen cycle and the impacts of anthropogenic activities on regional to global scales is largely hindered by the paucity of information about nitrogen inputs from human activities in fast-developing regions of the world such as the tropics. In this paper, we estimate nitrogen inputs and outputs in Brazil, which is the world's largest tropical country. We determined that the N cycle is increasingly controlled by human activities rather than natural processes. Nitrogen inputs to Brazil from human activities practically doubled from 1995 to 2002, mostly because of nitrogen production through biological fixation in agricultural systems. This is in contrast to industrialized countries of the temperate zone, where fertilizer application and atmospheric deposition are the main sources of anthropogenic nitrogen. In Brazil, the production of soybean crops over an area of less than 20 million ha, was responsible for about 3.2 Tg N or close to one-third of the N inputs from anthropogenic sources in 2002. Moreover, cattle pastures account for almost 70% of the estimated 280 × 106 ha of agricultural land in Brazil and potentially fix significant amounts of N when well managed, further increasing the importance of biological nitrogen fixation in the nitrogen budget. Much of these anthropogenic inputs occur in the Brazilian savannah region (Cerrado), while more urbanized regions such as the state of São Paulo also have high rates of nitrogenous fertilizer inputs. In the Amazon, rates of anthropogenic nitrogen inputs are relatively low, but continuing conversion of natural forests into cattle pasture or secondary forests potentially add a significant amount of new nitrogen to Brazil given the vast area of the region. Better measurements of biological fixation rates in Brazil are necessary for improving the nitrogen budgets, especially at a more refined spatial scale. [ABSTRACT FROM AUTHOR]

The holarctic mutualisms between Cembrae Pines (Pinus, Pinaceae) and nutcrackers (Nucifraga, Corvidae) comprise important textbook examples of interaction and coevolution. However, only recently we have learned to what extent nutcracker seed caching influences the ecology and biology of these pines. The North American mutualism between whitebark pine (Pinus albicaulis) and Clark’s nutcracker (Nucifraga columbiana) demonstrates the greatest array of consequences to the pine, particularly in fire-dependent communities in the northern Rocky Mountains. The impacts of Clark’s nutcracker seed-caching on whitebark pine are evident at multiple spatial and temporal scales, from tree growth form and fine-scale genetic structure and the timing of regeneration and community development to regional and rangewide genetic structure, and post-Pleistocene range expansion. [ABSTRACT FROM AUTHOR]

The Northern Pocket Gopher (Thomomys talpoides Richardson) is a small herbivory subterranean rodent. It is known as an eager digger and in areas with intense activity it is suspected of damaging young tree growth. Results from soil analysis and snow measurements are presented to describe the pocket gophers’ summer and winter environment within a ribbon forest in the forest-alpine tundra-ecotone on Niwot Ridge, Colorado Front Range. The distribution of snow and the structure of snow cover are influencing the pocket gopher’s life under cover. Soil analysis showed that pocket gopher activity modified the soil environment. The amount of coarse soil particles in the upper topsoil layers was increased compared to topsoil with no gopher disturbance. The distribution of organic matter within the upper 12 cm was more homogeneous in areas with gopher excavation. None of the damages found on young trees could be attributed to pocket gopher activities without question. The most obvious damages were reduced growth at the windward side (83 %) followed by crippled growth (60 %) and damages caused by snow fungi (32 %). In summary, the pocket gophers in the ribbon forests on Niwot ridge are actively modifying the soil environment by exposing mineral soil and increasing the likelihood of soil erosion by wind and water. There is, however, no evidence that pocket gophers are responsible for the visible prevalent damage on juvenile conifers. [ABSTRACT FROM AUTHOR]

The habitat-forming scleractinian coral Lophelia pertusa supports an ecosystem that is widely known to occur in the bathyal marine ecologic realm along deep shelves, oceanic banks, seamounts and continental margins. Therefore, L. pertusa is generally considered a ‘deep-water’ or ‘deep-sea’ coral. In contrast, this study analyses the environmental controls of this bathyal ecosystem where it is thriving well in the non-bathyal shallow-water setting of the Swedish Kosterfjord area (NE Skagerrak). This is one of several shallow-water L. pertusa occurrences in Scandinavian waters where saline and temperature stable oceanic waters intrude as topographically-guided underflows onto the inner shelf and adjacent fjords, driven by an estuarine circulation. The L. pertusa occurrence of the Säcken site in the northern Kosterfjord exists at 80–90 m water depth and only a few tens of metres beneath a permanently brackish surface water layer. At the depth of the coral patches, however, the hydrographic data reveal fully marine conditions, which are ensured by a deeper inflow of Atlantic water through the Norwegian Trench into the Skagerrak. SEM analyses of resin casts taken from dead L. pertusa skeletons yield an endolith assemblage dominated by boring sponges such as Cliona spp. (trace: Entobia ispp.), the boring bryozoan Spathipora, the fungus Dodgella priscus (trace Saccomorpha clava) and an unknown fungus (trace: Orthogonum lineare). Such a composition exclusively of heterotroph organisms resembles the Saccomorpha clava / Orthogonum lineare ichnocoenosis which is regarded as indicative for fossil and Recent, open marine, aphotic environments. This interpretation is supported by direct light measurements at the Säcken site, which indicate aphotic conditions for at least most of the year. The finding of bathyal communities in comparatively shallow waters is linked to factors that force deeper oceanic water masses to surface. Such situations are likely to be expected where an estuarine circulation prevails, or in deep-sea basins bordered by narrow shelves and with local upwelling cells driven by the wind regime, facilitating the intrusion of eutrophic deeper waters to shallow depths — including the benthic communities. This circumstance reveals a major potential pitfall in the palaeobathymetric interpretation of fossil L. pertusa occurrences, which tend to be interpreted as bathyal palaeoenvironments. Strikingly, almost all known exposed ancient L. pertusa locations (e.g. Rhodes and Messina Strait in the Mediterranean Sea or the Cook Strait, New Zealand) derive from tectonically active regions with steep bathymetric gradients and a specific confined topography which could have forced deep water to the near surface. [ABSTRACT FROM AUTHOR]

Samples of Lophelia were taken at two localities in the Lindos Bay Clay (Lower Pleistocene) of the Rhodes Formation on the Dodecanese Island of Rhodes. At a coastal exposure at Vasphi, northeast Rhodes, about 200 fragments of Lophelia were collected in situ from the clay and surface preservation of these is consequently particularly fine. The second collection of material was made at an exposure south of Lardos, about 35 km further south. This material comprised some 800 fragments of Lophelia collected both in situ and loose; preservation quality of the surfaces of these is variable. Both collections derive from single fl at beds of coral fragments. Bioerosion of the corals shows a good diversity, comprising about 18 ichnotaxa, five in open nomenclature, including: Orthogonum lineare, Saccomorpha clava and other microborings (probably exclusively of endolithic fungi), Oichnus isp. (pits and holes of various forms, probably all deriving from foraminifers), dish-shaped etchings possibly produced by the foraminifer Hyrrokkin sarcophaga, Palaeosabella prisca (polychaete worm borings), Caulostrepsis isp. (polychaete borings), probable Maeandropolydora isp. (polychaete borings), Talpina isp. (phoronid borings), Podichnus centrifugalis (attachment scars of brachiopods), Centrichnus eccentricus (attachment scars of anomiid bivalves), Gnathichnus pentax (tooth scratches by regular echinoids), and Entobia ispp. (borings of endolithic sponges). Three small, radiating forms around a millimetre in size are difficult to attribute to particular tracemaking organisms. They are retained in open nomenclature as Semidendrina-form (possibly foraminifera borings), a non-camerate radiating form and a hirsute camerate form. No ctenostome bryozoan borings were observed. Talpina isp. is abundant at Vasphi but scarce at Lardos. Otherwise the relative abundance of the trace fossils is comparable at the two localities. The total amount of bioerosion varies considerably in different parts of the coral skeleton. On the basis of SEM imagery, three categories of bioerosional intensity are introduced: 1, slight bioerosion; 2, medium bioerosion, and 3, heavy bioerosion. The distribution of Gnathichnus pentax and the absence of Radulichnus inopinatus indicates an aphotic environment. The microbioerosional assemblage correlates with the Saccomorpha clava / Orthogonum lineare Ichnocoenosis, which also indicates an aphotic seafl oor. [ABSTRACT FROM AUTHOR]

This study focuses on bioerosion of an aphotic deep-water coral mound, the Propeller Mound, in the northern Porcupine Seabight. The predominant framework builder is the cosmopolitan cold-water coral Lophelia pertusa. We demonstrate bioerosion patterns within the skeleton of L. pertusa using a new embedding method under vacuum conditions with subsequent scanning electron microscope analysis. Following this method, 23 ichnospecies are documented and related to heterotrophic organism groups such as Bacteria (1), Fungi (12), Bryozoa (1), Foraminifera (3), and Porifera (6). Predominant endolithic sponges in the framework of L. pertusa are Alectona millari and Spiroxya heteroclita. Owing to its characteristic growth and surface ornamentation, trace casts of Spiroxya heteroclita are correlated to the well-known trace fossil Entobia laquea. Investigations of thin sections of post-mortem skeletons show a clearly pronounced endolithic tiering of three penetration depths. The analysed samples are divided into three macroscopic preservational stages differing in post-mortem age, and exposure of the framework. Bioerosion affects bare parts of the coral skeleton. Bioeroders preferably settle on one side of an upright growing colony. A succession usually starts with the infestation by bacteria and fungi. Contact zones of epiliths are preferred areas for penetration by endoliths. Sponges and foraminifers appear 10 cm below the zone of living polyps, followed by boring bryozoans 15 cm below. However, in one case the sponge Spiroxya heteroclita is documented in the skeleton of living polyps. Frameworks exposed to water host 19 ichnospecies, thus forming the most diverse ichnocoenosis, whereas nine ichnospecies are documented in coral specimens buried by sediment. Mapping of epi- and endoliths in living and freshly necrotic colonies represents a useful tool for monitoring environmental conditions and define ecological “health” of deep-water corals in a rapid large-scale assessment of the state of coral reefs. [ABSTRACT FROM AUTHOR]

An overview of preliminary results from a series of recent Remotely Operated Vehicle (ROV) dives on the deep-water coral provinces of the Porcupine Bank, Irish continental margin, NE Atlantic is presented. The Porcupine Bank exhibits numerous giant carbonate mounds (up to 100s of metres in height) that occur predominantly, although not exclusively, on topographic ridges. The results revealed that, although these ridges have a tectonic origin, contemporaneous activity is typified by erosion due to strong hydrodynamic controls. The carbonate mounds are colonized by a variety of suspension feeders and associated fauna including framework-building corals (e.g., Lophelia pertusa and Madrepora oculata) although dense coral reef-like fauna coverage is not evident at present. The ecology of the carbonate mounds varied widely. Sessile megafauna, such as sponges, gorgonians and framework-building corals (e.g., Lophelia pertusa), were abundant on some of the carbonate mounds. Other mounds were relatively barren and appeared to be undergoing a natural senescence, with a much lower biomass of megafauna than is typical of shallow-water coral reefs. Some mounds had been damaged by demersal trawls, with smashed coral and lost gear common, whereas others appeared relatively pristine with occasional evidence of man-made litter. [ABSTRACT FROM AUTHOR]

The Davidson Seamount is located 120 km to the southwest of Monterey, along the California coast, USA. It is 2,400 m tall; yet, it is still 1,250 m below the sea surface. In May 2002, 90 hours of digital video was recorded from all depths of the Davidson Seamount, using a remotely operated vehicle, and deep-sea coral specimens were collected. Preliminary analyses indicate that 20 coral taxa were found, and they were almost exclusively located in high relief, ridge areas. Other species were noted on or adjacent to the corals. Because of its pristine nature, as well as human threats and great potential for education, the Davidson Seamount is under consideration for protection as part of the Monterey Bay National Marine Sanctuary. [ABSTRACT FROM AUTHOR]

There is much debate about how to protect deep-sea coral and sponge ecosystems using the data currently available. The Aleutian Islands in Alaska contain some of the most abundant, diverse, and pristine deep-sea coral and sponge ecosystems on Earth. From 1990 to 2002, U.S. federal fishery observer data indicates approximately 2,176,648 kg of coral and sponge bycatch occurred in the Aleutian Islands, equaling 52 % of all coral and sponge bycatch in Alaska. Coral and sponge bycatch rates in the Aleutians were over 12 times the rate in the Bering Sea or Gulf of Alaska. The National Marine Fisheries Service (NMFS) estimates that 87 % of coral bycatch and 91 % of sponge bycatch is caused by bottom trawling in the Bering Sea/Aleutian Islands management areas. The conservation organization Oceana developed an interdisciplinary fishery management approach to mitigating adverse impacts of fishing on deep-sea coral and sponge ecosystems, which has been used by NMFS to formulate a habitat protection alternative for the Aleutian Islands that is being considered in an Environmental Impact Statement. The Oceana Approach is offered as a cost effective model for reducing the adverse effects of fishing on deep-sea coral and sponge ecosystems. The approach uses observer data to identify areas of high coral and sponge bycatch rates to develop a comprehensive management policy that allows bottom trawling only in specific designated areas with high fish harvest and low habitat impacts. All areas not specified as open would be closed to bottom trawling. To prevent effort displacement, bottom trawl effort is reduced by the amount that historically occurred in areas that would become closed. The Oceana Approach also includes coral and sponge bycatch limits and a plan for comprehensive seafloor research, mapping, and monitoring. An enforcement strategy for these management measures is developed based on agency capabilities, and includes increased observer coverage, vessel monitoring systems, and electronic logbooks. This approach allows for continued catch of target species with minimal adverse impacts on coral and sponge habitat. Successful implementation of the Oceana Approach will protect areas of high known trawl impacts to deep-sea coral and sponge ecosystems and prevent trawl effort from moving into new, unexplored areas. The methodology is recommended for application to other regions and should be adjusted based on the available fishery and biological data for each region. [ABSTRACT FROM AUTHOR]

The deep-sea (>200 m) represents the largest portion of the ocean, but it is probably the least understood because of the technological challenges and financial resources required to explore and research this environment. With the advancement of underwater technology, astonishing images of deep-sea corals living at depths from the surface to greater than 1000 m are now becoming available to both policy makers and the public. More specifically, in the North Atlantic Ocean, these images have led many countries to begin to assess the distribution, status, health, and potential threats faced by these important ecosystems, which appear to be connected by the uniting influence of the Gulf Stream and its associated currents. Since deep-sea coral ecosystems extend beyond national boundaries and encounter similar threats, it was determined that a cooperative effort on both sides of the Atlantic could be beneficial to maximize available resources, share expertise, and exchange data to rapidly increase scientific understanding of deep-sea coral ecosystems. Thus, an international Deep-Sea Corals Workshop was held to identify critical information needs related to: locating and mapping deep-sea corals; understanding more about coral biology and ecology; and using specific deep-sea coral species as indicators of climate change. Priority information needs identified at the workshop were the need to: (1) conduct both low- and high-resolution mapping to locate and characterize deep-sea coral habitats; (2) conduct research on factors that influence deep-sea coral life history patterns; (3) examine how they function as habitat for fish and invertebrate species; (4) develop a comprehensive inventory of deep-sea coral species; and (5) further efforts to analyze past climate changes and to improve climate forecasting models. Described herein are: the results of the Deep-Sea Corals Workshop; other events with a focus on deep-sea corals; and potential pathways to increase U.S.-international collaborative partnerships. [ABSTRACT FROM AUTHOR]

Zooxanthellate scleractinian corals have been shown to preserve important archives of seasonal variations of climate variables, such as sea surface temperature, salinity, and productivity. By analogy, the recognition of correlated chemical signals in azooxanthellate deep-water corals may provide an important new approach to help unravel the role of intermediate and deep waters in determining climate variability. A first step to determine the suitability of deep-water scleractinian corals as potential paleoceanographic-paleoclimatic tools requires the demonstration of coherent geochemical signals in their skeletons. With this in mind, trace and minor element ratios Sr/Ca, Mg/Ca, U/Ca, B/Ca, P/Ca, Ba/Ca and Mn/Ca have been measured in two deep-water solitary scleractinian corals (Desmophyllum dianthus) collected from Last Glacial submerged banks in the Mediterranean basin and in the Great Australian Bight. Most elements show distinct, highly correlated patterns of variation. Although preliminary, these results illustrate the potential use of trace and minor element concentrations in the deep-water scleractinian corals to provide new constraints on the composition and evolution of intermediate and deep waters and thus introduce new perspectives in paleoceanography, such as the assessment of changes in both deep-sea nutrient chemistry and ocean circulation. [ABSTRACT FROM AUTHOR]

The longest available time series on ocean currents indicates that the southward flow of water from the Greenland Sea is weakening, and that correlative large-amplitude changes have occurred in the rate of formation of intermediate Labrador Sea water. These have been linked to changes in regional climate which, if trends continue, could within 30 years alter the flow of the North Atlantic Drift and possibly interrupt the formation of Labrador Sea water, profoundly affecting regional climates, marine ecosystems and fisheries. We are attempting to use the carbonate skeletons of cold-water corals to find out how rapidly and how often the thermohaline circulation of the NE vs. NW Atlantic has changed in the past, just as tree rings and ice cores are used to investigate climate change on land. We have focussed on the NE Atlantic for our preliminary work, notably the Faroe-Shetland Channel: a major gateway between the Atlantic Ocean and the Norwegian Sea. Warm North Atlantic Drift water passes north through this channel on the surface, warming northern Europe. Cold Norwegian Sea Overflow Water returns at depth, contributing to the formation of North Atlantic Deep Water. Existing records are too short to allow conclusions regarding recent temporal changes in this inflow, so proxies are sought. We have analysed live-collected Lophelia pertusa skeletons collected in October 2001 using a ring dredge from RV Scotia along the worlds longest-running hydrographic transect (from 1893). Corals were sectioned using a slow-speed Isomet saw, and sampled for isotopic analysis using a Merchantek micromill. Observation of sectioned corals revealed dense-less dense couplets, as in every coral studied to date from tropical to deep cold-water environments worldwide. We sampled circumferentially, in the centres of individual bands, so as to produce temperature estimates using the “lines” technique of Smith et al. (2000). The results were simultaneously encouraging and confusing. Each of the coral samples generated lines from which temperatures could be estimated. Dense skeletal bands had lower temperatures than the less-dense bands, hence we conclude these were winter and summer bands, respectively. The mean annual temperature (MAT) range determined from one of the corals was 3.8°C. Pooling results from several corals yielded a lower estimate for MAT range: 2.3°C. The absolute temperatures from the corals, however, were somewhat lower than the instrumental record with “winter” records being more depleted than the “summer values”. This was unexpected and shows that determining detailed climate records from L. pertusa may be more difficult than hoped. [ABSTRACT FROM AUTHOR]

Like other biogenic carbonate that can be dated, aragonite skeleton of deep-sea corals is a potential archive of oceanographic changes over time. Stable isotope analysis is commonly used in paleoceanographic reconstruction of past seawater temperatures, however, offset from isotopic equilibrium as well as recent observations about isotope distribution with the micro-structure of deep-water corals implies non direct paleoclimate reconstructions. Here we test the influence of the sampling scale on oceanographic interpretations. The stable isotope composition for different modern calyxes of Lophelia pertusa has been analyzed at different scales using either a macro or a micro-sampling technique. The comparison of the obtained results from the two sampling techniques shows that the isotopic variability observed with the micro-sampling is twice the one with macro-sampling. Moreover the macro-sampling is not an average of what happens at a more precise scale. Nevertheless a realistic seawater temperature estimate can be retrieved using the equation of Smith et al. (2000) for both the macro and the micro-sampled corals. However, a test of the reproducibility on a single calyx reveals important isotopic inhomogenities at a very fine scale (∼µm), yielding an external reproducibility of the seawater temperature estimates of about ±0.7°C for micro sampled corals. [ABSTRACT FROM AUTHOR]

It has been suggested that the deep-sea gorgonian coral Primnoa resedaeformis may be an important paleoceanographic archive. Seventeen colonies collected from the upper slope of the NW Atlantic margin (229 – 447 m) were analyzed to see if skeletal Mg/Ca is related to temperature. Analyses were focused on the calcite cortex region of skeletal sections to avoid interference from organic Mg in the horny layers found closer to the center of sections. Comparison of bulk skeletal Mg/Ca with hydrographic temperature yielded the relationship Mg/Ca (mmol/mol)=5 (+/− 1.4) T (°C)+64 (+/− 10). This relationship was used to calibrate profiles of Mg/Ca measured across the annual rings of one large, well-dated colony, over the period 1950–2002. Mg/Ca profiles were broadly consistent among three sections spaced 10 cm apart along the main trunk of the colony. These profiles were in general agreement with the local instrumental record of temperature at 375 – 450 m. Some discrepancies between the coral and instrumental records of temperature may be a result of chronological error, poor sampling density, or additional factors influencing Mg partitioning in the coral. Overall, these preliminary results support the hypothesis that temperature drives Mg/Ca in the skeletal calcite of this species. It appears that environmentally meaningful records from Primnoa resedaeformis will be found at decadal scales or longer. [ABSTRACT FROM AUTHOR]

Two samples of the calcitic deep-sea coral Primnoa resedaeformis have been analysed for Mg/Ca ratios by micro-beam methods ( laser-ablation ICP-MS and electron microprobe). Continuous profiles of Mg/Ca have been studied with the aim of establishing the reproducibility of the variations in different parts of the coral, and therefore the potential use of Mg/Ca as a paleoceanographic or paleoclimatic tracer. A method of spectral decomposition based on box-filter smoothing has been developed for analysing the signals. This method shows that all profiles measured contain some degree of irreproducibility. Much of this irreproducibility appears to be white-noise added by the analytical methods. The amplitude of this noise is around 15 % of the signal average for the Nd-YAG laser-ablation system at Memorial University of Newfoundland, 5–6 % for the electron microprobe at Dalhousie University, and 4–4.5 % for the ArF Excimer laser-ablation system at the Australian National University. In the case of the LA-ICP-MS analyses, this noise may relate to uneven ablation of material from the coral and/or an uneven size distribution of particles entering the ICP-MS plasma. For the most stable system (ANU’s LA-ICP-MS), features on distance scales smaller than 150–200 µm will be obscured by the noise, and features smaller than 500 µm should be interpreted with caution. There is some evidence that the coral itself contains compositional heterogeneity, although reproducibility is mostly limited by instrumental noise. We recommend that several analytical profiles be compared before any attempt is made to interpret Mg/Ca variations in terms of paleoceanographic changes. [ABSTRACT FROM AUTHOR]

Lophelia pertusa is a deep-sea scleractinian coral (azooxanthellate) found on the continental margins of the major world oceans. Built of aragonite it can be precisely dated and measured for stable isotope composition (C–O) to reconstruct past oceanic conditions. However, the relation between stable isotope and skeleton microstructures, i.e. centres of calcification and surrounding fibres, is crucial for understanding the isotopic patterns. Values for δ18O and δ13C in Lophelia pertusa were determined at a micrometer scale using an ion microprobe (SIMS - Secondary Ion Mass Spectrometry). In this coral species, centres of calcification are large (50 µm) and arranged in lines. The centres of calcification have a restricted range of variation in δ18O (−2.8 ± 0.3 ‰ (V-PDB)), and a larger range in δ13C (14.3 to 10.9 ‰ (V-PDB)). Surrounding skeletal fibres exhibit large isotopic variation both for C and O (up to 12 ‰) and δ13C and δ18O are positively correlated. The C and O isotopic composition of the centres of calcification deviate from this linear trend at the lightest δ18O values of the surrounding fibres. The fine-scaled variation of δ18O is probably the result of two processes: (1) isotopic equilibrium calcification with at least 1 pH unit variation in the calcification fluid and (2) kinetic fractionation. The apparent δ13C disequilibrium in Lophelia pertusa may be the result of mixing between depleted δ13C metabolic CO2 (respiration) and DIC coming directly from seawater. This study underlines the close relationship between microstructure and stable isotopes in corals. This relationship must also be taken into consideration for major elements like Mg and trace elements (U-Sr-Ba) increasing the reliability of the geochemical tools used in paleoceanography. [ABSTRACT FROM AUTHOR]

Benthic Foraminifera found attached to the deep-sea coral Primnoa resedaeformis may be used to establish paleo-coral locations long after the coral has disappeared. Recent coral research cruises have revealed that the coral on the Scotian Margin is in peril and in many cases no longer exists. Sea floor video footage suggests various fishing methods have destroyed much of the coral as it has in coastal areas off Norway and Alaska. To date deep-sea corals are sparse on the Scotian Margin; therefore evidence preserved in the sediment may establish whether corals were present and more abundant in the past. A representative assemblage of benthic foraminiferans found attached to the deep-sea coral Primnoa resedaeformis may be the evidence necessary to provide presence/absence indicators long after the coral has disappeared. Both foraminiferal species are known to be only associated with the coral, and distortion of the ventral side (attached) of common foraminiferal species found in the sediment, may provide a clue to past coral habitat. Identifying a deep-sea coral paleo-habitat indicator provides insight into the extent to which it existed. Video footage from coral cruises over the last three years indicates that coral and fish go hand in hand, an important observation for a region where fishing comprises 23 % of the local economy. Twenty-eight foraminiferal species were found in a range of abundances on nine deep-sea coral specimens of Primnoa resedaeformis. Attached foraminiferans are found on the basal sections of the coral where they colonize onto the hard calcite substrate. One of the more common and consistent foraminiferal species found attached to the coral, Discanomalina semipunctata, is not found commonly on the continental margin in non-coral areas and may provide in situ evidence of past coral habitat. [ABSTRACT FROM AUTHOR]

The rate of discovery of reefs of the cold-water coral Lophelia pertusa (Linnaeus, 1758) has been remarkable, and attributable to the increased use of underwater video. These reefs form a major three-dimensional habitat in deeper waters where little other ‘cover’ for fish is available. They are common in the eastern North Atlantic, and occur at least in the western North Atlantic and off central Africa. There are also other non-reef records of Lophelia in the Atlantic, and in Indian and Pacific oceans. Thus, not only are these reefs a significant habitat on a local scale, but they may also provide an important habitat over a very wide geographic scale. The present study examined the association of fish species with Lophelia in the Northeast Atlantic, including the Trondheimsfjord and Sula Ridge in Norway, Kosterfjord in Sweden, Darwin Mounds west of Scotland, and Rockall Bank, Rockall Trough and Porcupine Seabight off Ireland. The fish fauna associated with a shipwreck west of Shetland was also studied. Data were collected from 11 study sites at 8 locations, using 52 hours of video and 15 reels of still photographs. Video and still photographs were collected from (1) manned submersible, (2) surface controlled remotely operated vehicle (ROV), (3) a towed “hopper” camera, (4) wide angle survey photography (WASP), (5) seabed high resolution imaging platform (SHRIMP), and (6) an in situ time-lapse camera “Bathysnap”. It was possible to identify 90 % of fish observed to species level and 6.5 % to genus or family level. Only 3.5 % of the fish were not identifiable. A guide to the fishes is given at http://www.ecoserve.ie/projects/aces/. Twenty-five species of fishes from 17 families were recorded over all the sites, of which 17 were of commercial importance and comprised 82 % of fish individuals observed. These commercial fish species contribute 90 % of commercial fish tonnage in the North Atlantic. The habitats sampled were comprised of 19 % reef, 20 % transitional zone (i.e. between living coral and debris zone), 25 % coral debris and 36 % off-reef seabed. Depth was the most significant parameter in influencing the fish associated with the reefs, both at the species and family level. There was a complete separation of sites above and below 400–600 m depth by multi-dimensional scaling (MDS) analysis. Less distinct assemblages of fish species were associated with each habitat. Fish species richness and abundance was greater on the reef than surrounding seabed. In fact, 92 % of species, and 80 % of individual fish were associated with the reef. The present data indicates that these reefs have a very important functional role in deep-water ecosystems as fish habitat. [ABSTRACT FROM AUTHOR]

Deep-sea dredging of sediment-starved steep reliefs in the Strait of Sicily (cruise CS96 of RV Urania) recovered various benthic organisms previously unknown or poorly documented in the Mediterranean basin. This Mediterranean case-study refers to deep coral substrates represented by loose or cemented skeletal remains of Desmophyllum, Lophelia and Madrepora, subfossil giant oyster shells, micriticised sponges, from c. 250–1000 m depth. Here we present some of the more remarkable species: one foraminiferan (Planogypsina?); the sponges Stylocordyla pellita, Sphinctrella gracilis and Siphonidium ramosum; a bioluminescent zoantharian (still unidentified); the boring actinian Fagesia loveni; the stoloniferous octocoral Scleranthelia musiva; the gorgonian Dendrobrachia fallax; and the holothurian Psolidium complanatum. [ABSTRACT FROM AUTHOR]

Seamounts are drowned volcanoes rising from abyssal depths. Fishes on seamounts exploit a range of landscape features that likely enhance probabilities of prey capture and reduce predator success. The epifaunal community on seamounts is dominated by suspension-feeders of which deep-water corals are a dominant element. Such taxa are widespread components of seamount landscapes but their functional role in mediating the distribution and abundance of fishes remains unknown. Here we propose a hierarchical habitat classification matrix, which includes deep-water corals, as a foundation for partitioning seamount landscapes in which fishes are observed. This scheme is based on our observations of fish distributions from the New England Seamounts, as well as literature review. Features of an idealized seamount landscape were divided at multiple spatial scales and included features at habitat class, subclass and microhabitat levels. Habitat classes were divided by major sediment types (i.e., basalt, fine grained sediments). Habitat subclasses included pavement, ridges, walls, ledges and tubes for basalt substrates and flat sediment, ripples and waves for fine-grained sediments. Microhabitat features were classified as flow related features, emergent structures (i.e., geologic and biologic including deep-water corals), and other biogenic structures (e.g., coral debris, depressions, burrows). Variations in the distribution of structures at multiple spatial scales can influence boundary flows and the ability of fishes to search for prey (e.g., where active searching by swimming can occur, where pelagic prey delivery is sufficient when station-keeping) and avoid predators (e.g., the ability to efficiently exhibit various avoidance behaviors such as shelter seeking). Placing fish abundance data in such a matrix of habitat types enables a variety of statistical approaches for testing for non-random distributions of fishes on seamounts and quantifying the functional role of corals as fish habitat. [ABSTRACT FROM AUTHOR]

The metazoan meiofauna associated with Lophelia pertusa reef degradation zones in the Belgica Mound province (Porcupine Seabight, North-East Atlantic) was studied in the framework of the Atlantic Coral Ecosystem Study (ACES; EC Fifth Framework Research Program). Attention was focused on the influence of and differences between different microhabitat types: dead coral fragments, glass sponge skeletons and the underlying sediment. This study demonstrates the importance of dead Lophelia pertusa framework and associated substrates for meiofauna along the European continental margins. The presence of these large biogenic structures on the seafloor of the continental margin (1) enables more taxa to be present and (2) particularly favours harpacticoid copepods, naupliar larvae and polychaetes. The meio-epifaunal community on these substrates significantly differs from the meio-infaunal community in the underlying sediment. This is mainly due to a much lower dominance of nematodes and a higher relative abundance of most other taxa, especially harpacticoids, naupliar larvae and polychaetes, in the latter habitat. This situation is comparable to that of epiphytic assemblages. Dominance of nematodes is low. The meio-infaunal assemblage in the underlying sediment is characterized by low densities. There are clear indications that cold-water coral degradation zones are biologically very diverse, in terms of species richness as well as equitability. Of all microhabitat types, coral fragments support the most diverse communities, whereas the underlying sediment is the least diverse. [ABSTRACT FROM AUTHOR]

High densities of fishes in aggregations of deep-water corals (e.g., of the genera Primnoa, Paragorgia, Paramuricea) do not necessarily indicate that corals are important habitats in terms of population processes. Frequency dependent distribution models provide a basis for assessing the role of deep-water corals. It is necessary to understand the overall habitat-related distributions of fish species, at particular life history stages, in order to assess the particular role of corals. Examining the landscape for ecologically equivalent habitats is one approach for assessing the importance of coral habitats. Measures of the functional equivalence of habitats are demonstrated, as an example, for sites from the Gulf of Maine on the northeast United States continental shelf. Fish census data based on surveys with a remotely operated vehicle in 2003 showed that communities in habitats dominated by dense corals and dense epifauna were functionally equivalent when compared with five other less complex habitats (e.g., boulder with sparse coral cover). Comparison of species-individual curves showed that sites with dense coral and dense epifauna habitats supported only moderate levels of fish diversity when compared with other sites. Further, density of Acadian redfish (Sebastes fasciatus) in dense coral and dense epifauna habitats, where this species was dominant, was not statistically different but was higher than an outcrop-boulder habitat with sparse epifauna (the only other site where this species was abundant). Such data suggest that coral habitats are not necessarily unique but have attributes similar to other important habitats. However, the level of their importance in the demography of fish populations and communities remains to be demonstrated. Focusing conservation efforts for deep-water corals on their perceived value to exploited species, without good demographic information on fish populations, may ultimately leave corals open to destructive fishing practices if new and contrary information emerges. Conservation efforts for corals, in the absence of explicit ties to managed fish species, might do better emphasizing the intrinsic value of corals, their slow growth, high sensitivity to disturbance, and the questionable potential for recovery. [ABSTRACT FROM AUTHOR]

Colonial non-zooxanthellate corals from deep-water coral reefs, Lophelia pertusa and Madrepora oculata, produce large amounts of extracellular mucus (EMS). This mucus has various functions, e.g., an antifouling capability protecting the coral skeleton from attacks of endolithic and boring organisms. Both corals show thick epithecal and exothecal skeletal parts with a clear lamellar growth pattern. The formation of the epitheca is unclear. It is supposed that the EMS play a central role during the calcification process of the epithecal skeletal parts. Staining with the fluorochrome tetracycline has shown an enrichment of Ca2+ ions in the mucus. In order to investigate this hypothesis, the protein content of the mucus and the intracrystalline organic matter from newly formed epithecal aragonite of Madrepora oculata was determined via sodium dodecyl sulfate (SDS) gel electrophoresis. Identical band patterns within both substances could be detected, one around 45 kDa molecular weight and a cluster around 30–35 kDa molecular weight. The occurrence of identical protein patterns within the mucus and in the newly formed aragonite confirms the idea that the mucus plays an important role during the organomineralization of the coral epitheca. [ABSTRACT FROM AUTHOR]

A number of reefs are found along the coast of northern Norway, and a cluster of particularly high reefs off Troms County at 70°N are known collectively as the Fugløy Reef. The reefs, up to 40 m high and more than 200 m wide, consist mainly of the reef-building Lophelia pertusa. Most of the reefs identified in the study area are located on moraine ridges in water depths of 140–190 m, and in water masses dominated by the relatively warm and saline Norwegian Current. Several of the reefs are located on the flanks of channels incising the moraine highs, where currents are tidally dominated and periodically reach velocities of 30 cm/s. Gravity cores were acquired from the reefs and their surroundings, and thorough analyses of the sampled sediments provide valuable information about three (paleo-) sedimentary environments surrounding the reefs. The immediate vicinity of the reefs consists of coarse and unsorted deposits that are interpreted to be moraine material deposited by the retreating inland ice. Elevated current velocities have prevented fine sediments from settling since the ice retreated. The second province is a pockmarked basin at water depths down to ∼300 m. Gravity cores from the basin reveal silty sand deposits of more than 4 m thickness representing postglacial sedimentation in the area. Gas analyses reveal that the hydrocarbons found in the sediments clearly are of biogenic origin, although it is somewhat enigmatic whether biogenic gas is the sole driving force behind the pockmarks in the area. No direct link between the reefs and the pockmarks is found. The third sedimentary province is characterised by resedimentation of coral debris, clearly illustrated by sorted deposits and U/Th-datings from the allochthonous deposits. Remobilisation of coral debris is modest in areal extent, but an important mechanism linked to the occurrence of the coral reefs. [ABSTRACT FROM AUTHOR]

As a result of the explorations carried out by the Colombian Marine and Coastal Research Institute (INVEMAR) between 1998–2002 along the Colombian Caribbean continental shelf and upper slope, the occurrence of azooxanthellate coral banks was suspected at three sites (from the northern to southern Colombian Caribbean coast): off La Guajira Peninsula, at a water depth of 70 m; off Santa Marta, at 200 m, and nearby the San Bernardo Archipelago, at 150 m). Each site exhibited particular bottom features (relief and substrate), suggestive of reef structures. The analysis of the fauna collected by bottom trawling at these sites showed that many of the fishes, mollusks, echinoderms, crustaceans, antipatharians, soft corals and bryozoans collected are characteristic dwellers of hard substrates or reef bottoms. At the first site (Guajira) the hard coral Cladocora debilis, was the most abundant; a total of 156 species of invertebrates and fishes were identified among the material collected at this site. At the second site (Santa Marta), 13 scleractinian species were collected, but Madracis myriaster, was the dominant species; another 102 species of invertebrates and fishes were also found. At the third site (San Bernardo) 19 scleractinian species were found, M. myriaster being the dominant. A total of 135 species of invertebrates and fishes were collected at this site. It is presumed that deep-sea coral banks have developed in these three settings, since many of the collected species are known to be hard or reef bottom dwellers. [ABSTRACT FROM AUTHOR]

Carbonate mounds (up to 200 m high) formed from the accumulated remains of cold-water corals (principally Lophelia pertusa and Madrepora oculata), associated calcareous fauna and interstitial sediment are present at 500–1000 m water depths west of Ireland. Seabed mapping datasets (side-scan sonar, multibeam echosounder, sub-bottom profiler and underwater video imagery) are presented here from the Belgica Mound province on the eastern Porcupine Seabight margin. The data, integrated within a Geographic Information System (GIS), provide an environmental context to mound development. Analysis of this multidisciplinary dataset and resultant facies map highlight differing sedimentary processes (e.g., sediment wave, barchan dune, gravel lag and sand ribbon development) operating under strong northward flowing bottom currents with sandy sediment supply where the influence of mound topography on benthic currents and sediment pathways is evident. Correspondingly, benthic current pathways and associated sediment transport also exert an influence on carbonate mound surface morphology and growth. Giant mounds show a transition from sediment waves that, with increasing coral colonisation, give way to banks of coral towards the mound summits. Smaller mound features (Moira Mounds) show sand entrapment as an important mound-forming process. [ABSTRACT FROM AUTHOR]

Carbonate mounds, identified as deep-water coral banks, have been reported recently from three provinces in the Porcupine Seabight, SW of Ireland. As yet, the mechanisms behind their formation and development are only partly understood. This contribution discusses their seabed appearance and present-day sedimentary environment, based on a large-scale TOBI sidescan sonar mapping carried out in 2002, and on detailed ROV video records from specific sites within the three mound provinces, collected in 2001. The study of the present-day characteristics and variability of these mounds can help to understand their development history in the past. The imagery clearly shows that the sedimentary environment in the Magellan and Hovland Mound provinces in the northern Porcupine Seabight is much quieter than in the current-swept Belgica Mound province on the eastern flank of the basin. In the latter area, for example, gravel lags and coarse sediments are found, together with patches of sorted sands, striations, barchan dunes and sediment waves. The difference in environment results in different mound appearances. The richest coral communities with the most abundant live coral occurrences are found in the Belgica province, while for example on the Magellan Mounds only a few live coral colonies are left. The present-day situation of the coral banks in the Porcupine Seabight thus illustrates the influence of the interplay between current and sediment dynamics on coral growth and mound development. [ABSTRACT FROM AUTHOR]

Since 1998, Woodside Mauritania Pty Ltd has been exploring for hydrocarbon deposits offshore from the Islamic Republic of Mauritania, in Northwest Africa. A 3-D seismic survey, undertaken in 1999–2000, revealed the presence of buried and seabed carbonate mounds at approximately 450–550 m water depth on the continental slope. These mounds are approximately 100 m in height, 500 m wide at the base, and cover a linear extent of at least 190 km. Core samples from the mounds were found to contain dead fragments of four species of cold-water corals: Lophelia pertusa, Madrepora oculata, Solenosmilia variabilis and Desmophyllum sp. In 2002, a preliminary towed camera survey revealed large areas of coral rubble at two mound sites suggesting that corals were previously a dominant component of the benthic community. A second video survey, in 2003, recorded some live hard coral polyps and a single live coral colony, probably L. pertusa, at one of the mound sites. Coral rubble at all sites surveyed was found to support epibenthic invertebrate and fish assemblages. The mound areas surveyed may have been exposed to physical impacts that have resulted in damage of coral colonies previously inhabiting these features. Based on the nature of the damage and past and present demersal fishing activity in the region, bottom trawling could have caused these impacts. The discovery of a significant deep-water reefal system offshore Mauritania has implications for future management of trawling and oil exploration activities. These issues are discussed in the context of the potential biodiversity significance and conservation importance of the carbonate mud mounds and their associated biological communities. [ABSTRACT FROM AUTHOR]

The dynamics that occur at the Porcupine Bank, Rockall Trough, are described in relation to the role the bank, and others like it, may play in the development of deep-water corals, such as Lophelia pertusa (L.), which occurs widely in the NE Atlantic. High productivity has been measured over the bank, and it appears that this productivity may be fuelled by an increase in nutrients available over the bank through winter convection which leaves dense, nutrient rich water on the bank. This dense water drains away slowly through the benthic boundary layer (BBL) providing a mechanism for downslope transport of organic material in the boundary layer. Processes such as rectification of diurnal tides and Taylor column formation generate closed circulation patterns around the bank and promote the retention of organic matter over the bank. Similar processes have been observed over other Rockall Trough banks, and the combination of these processes appear to promote the availability of food to the corals that inhabit the lower flanks of the banks, particularly on the coral-dominated carbonate mounds that also occur there. [ABSTRACT FROM AUTHOR]

The environmental sensitivies of cold-water corals and their associated biota are likely to be determined by the natural variability of the cold-water coral reef environment. The sensitivity of reef biota to sedimentation and resuspension events is largely unknown and the influence of seasonal phytodetrital deposition is poorly understood. Here we describe the use of a benthic photolander to monitor this variability by the Sula Ridge reef complex on the mid-Norwegian continental shelf and from the Galway carbonate mound in the Porcupine Seabight. The photolander provides a platform for time-lapse digital and film cameras to image the seabed while recording the current regime and optical characteristics (light transmission, backscatter and fluorescence) of the seawater. In its first two deployments carried out in 2001 and 2002 by the Sula Ridge the lander recorded a dynamic environment around the reef site with a tidal current regime and periods of sediment resuspension. Current speeds by the Sula Ridge reef complex reached a maximum of 28 cm s−1 and 70 cm s−1 on the Galway carbonate mound, reinforcing much speculation about the dependence of these communities on current-swept conditions. Seabed photographs show intense feeding activity of echiuran worms (Bonellia viridis) near the Sula Ridge reef complex pointing to rapid bioturbation of the sediment. Fish were recorded sheltering near sponges that had colonised glacial dropstones. Longer term monitoring in situ is needed for study of seasonal change, to identify functional roles of associated fauna and to monitor potential coral spawning events. Benthic landers and seafloor observatories have great potential in these areas. Only with a better understanding of the natural variability of the cold-water coral environment can informed decisions about the environmental sensitivity of cold-water coral reefs and their management be made. [ABSTRACT FROM AUTHOR]

The benthic deep-water coral fauna of the Shiribeshi Seamount, Japan, was examined using the JAMSTEC video archives of four submersible dives in July 2001. An observational dataset containing n = 2055 records was obtained. The vertical distributions of the deep-water gorgonians Family Primnoidae and Paragorgiidae were determined. Primnoid corals include at least one species, Primnoa resedaeformis pacifica (Kinoshita, 1907) and are distributed between 1030 m and 271 m in depth and at a water temperature of 0.24–1.11°. Paragorgiid corals were observed between 491 m and 178 m in depth and at a water temperature of 0.66–1.69°, in shallower and warmer areas than primnoid species. It was observed that deep-sea gorgonians on the Shiribeshi Seamount in the North-West Pacific region exhibit family zonation and vertical distribution patterns. The distribution of hydrocorals, unidentified sponges, shrimp, and nudibranchs was also recorded. This is the first report on a deep-sea gorgonian coral community inhabiting Japanese waters. [ABSTRACT FROM AUTHOR]

A database of deep-water alcyonacean records has been assembled using information that reaches back to the work of A.E. Verrill from the 1800s. These database records fall into two time periods, those from 1874 to 1920, and from 1950 to 2001. A total of 25 species in 10 families are so far known from the northeastern U.S. Most of these species are common in deeper waters of the continental shelf, with a few being restricted to the canyons and other slope environments. A comparison of western and eastern North Atlantic records indicates there is little similarity between the regions. In the cold-temperate to boreal part of the region there is about 41 % similarity of the “stoloniferous” and “massive body” soft coral species, but only about 28 % similarity amongst all the “gorgonian” species. In the warm temperate part of the region the similarity for all groups is less than 10 %. Deep-water alcyonaceans are strongly impacted by bottom fishing gear so it is likely that modern distributional records will not be exactly similar to those from deep in the past. [ABSTRACT FROM AUTHOR]

The Institute of Marine Research commenced a program for mapping and assessment of Lophelia reefs in 1997. It was initiated by reports from fishermen claiming that bottom trawling damaged deep-water coral reefs. The strategy was to survey coral sites reported in the literature and by the fishermen. This has provided an extensive database of coral occurrences, both damaged and undamaged sites. A number of major coral reefs have been identified, which has provided a better understanding of the morphology of Lophelia reefs and where they are likely to occur. We are now able to identify potential coral areas by analysing seafloor topography on maps. Fast and reliable ground-truthing methods using simple and inexpensive systems have been developed. Mapping and quantification of corals demand more advanced instrumentation, such as singlebeam and multibeam echo sounders in combination with data processing software allowing coral reefs to be detected in real time. Systems providing real time presentation of multibeam data are especially useful in combination with Remotely Operated Vehicle (ROV) positioned with acoustic navigation systems. We suggest the following mapping procedure: 1) acoustical reef detection followed by multibeam mapping, preferably along with collection of seismic reflection data. 2) ground-truthing with a tethered video camera platform or an ROV. The position of the observation platform is plotted online and draped on the multibeam maps, either in 2D or 3D mode. Examples from the reefs on Sula, Røst, Træna and Fugløy are given. [ABSTRACT FROM AUTHOR]

Submarine canyons are structurally complex habitats known to support high densities and diversity of megafaunal organisms. This study describes deepwater corals and their habitats in The Gully, the largest submarine canyon in eastern North America, situated at the Canadian margin off Nova Scotia. Video recordings of the seabed were made along 49 transects, at depths between 110 and 544 m, using a tethered video camera system. The Gully has a high diversity of habitats with steep bedrock outcrops, high relief bottom with ledges of semi-consolidated mudstone, as well as level soft bottoms and areas with gravel. In total 95 megafaunal taxa were observed of which 16 species were corals. There was a strong, positive correlation between the total number of megafaunal taxa and number of coral species along transects, suggesting that coral diversity is a good indicator for overall megafaunal diversity. Corals were present in most parts of the canyon, and up to 11 species were observed along a single transect. The distribution patterns of corals were mainly related to distance along the axis from the canyon head and type of seabed substratum. The highest abundance of corals was found on the western side in the outer part of the canyon and is probably related to circulation patterns with a higher load of particulate matter in the out-fl owing water. Nephtheid soft corals, mainly Duva florida, were most frequent and were found within the whole depth range. Gorgonian corals were observed only deeper than 340 m. Except for Acanella arbuscula and Radicipes gracilis, which are anchored in mud, the gorgonians were mainly confined to areas with cobble and boulder and in a few cases to semiconsolidated mudstone. Multivariate analyses were applied to identify groups of transects and species, and to indicate which environmental factors control the distribution of corals and other megafauna in The Gully. [ABSTRACT FROM AUTHOR]