Deep-water Habitats Research Articles

Two new deepwater Peyssonnelia species, Peyssonnelia iridescens and Peyssonnelia gigaspora (Peyssonneliaceae, Rhodophyta) from Puerto Rico, Caribbean Sea

Ballantine D.L. and Ruiz H. 2010. Two new deepwater Peyssonnelia species, Peyssonnelia iridescens and Peyssonnelia gigaspora (Peyssonneliaceae, Rhodophyta) from Puerto Rico, Caribbean Sea. Phycologia 49: 537–544. DOI: 10.2216/09-88.1Two new distinctive Peyssonnelia species are described from deepwater habitats in southwestern Puerto Rico. Peyssonnelia iridescens possesses a distinctive bluish iridescent fringe and forms loosely adherent blades up to 6.0 cm across. The crusts possess a Peyssonnelia atropurpurea-type vegetative organization. Tetrasporangia are cut off distally from apical perithallial cells and measure up to 53 µm wide × 135 µm long. Carposporangia measure 25–30 µm in their largest dimension and are formed in elongate nemathecia. Peyssonnelia gigaspora is variously coloured, tan to reddish, with obvious radial striations and reddish spots when living. The crusts are closely appressed to the substratum and normally measure up to 130 µm in thickness, but are occasionally 200 µm thick and possess the Peyssonnelia rubra-type vegetative organization. Tetrasporangia are ovate and extremely large, measuring up to 100 µm wide × 250 µm long, and differentiate from the proximal paraphysal cell, thus being situated in an intercalary position.

Suitability of mineral accretion as a rehabilitation method for cold-water coral reefs

Extensive areas of the cold-water scleractinian Lophelia pertusa have been damaged due to the impact of bottom-trawling and natural recovery is slow or absent. Here we evaluate a method for coral reef rehabilitation intended to enhance coral transplant survival and growth, i.e. mineral accretion by electrolysis in seawater. Electrolysis in seawater produces a semi-natural substrate in the form of aragonite (CaCO 3). The method has been used in coral reef rehabilitation programmes in tropical coral habitats but has so far not been tested in temperate deep-water habitats. A controlled laboratory experiment was performed to test the effect of the substrate per se and different levels of applied current densities (0.00–2.19 A m −2), including galvanic elements (Fe|Zn), on coral fragments attached to the cathodes. The studied responses were; growth rate, budding frequency, mortality, and general health status (degree of polyp activity). We found that the budding frequency differed significantly between treatments, with higher frequencies in low current density treatments. Significant differences were also found in the frequency distribution of calices displaying a growth of ≥ 2 mm yr −1, with higher frequencies in the lowest applied current density (LI), controls, and galvanic elements. Growth rates were slightly higher in LI, although non-significant. Zero mortality was observed in the control group as well as in LI. The degree of polyp activity was not affected by the treatments. These results are in part congruent with earlier studies and the method is found suitable for L. pertusa. The positive effects were mainly restricted to the lowest applied current density treatment (0.06 A m −2). The optimal current density level is hereby found to be considerably lower than levels used in previous studies and provide new guidelines for what levels to use in rehabilitation programmes with this method.

Developmental plasticity of shell morphology of quagga mussels from shallow and deep-water habitats of the Great Lakes

The invasive zebra mussel (Dreissena polymorpha) has quickly colonized shallow-water habitats in the North American Great Lakes since the 1980s but the quagga mussel (Dreissena bugensis) is becoming dominant in both shallow and deep-water habitats. While quagga mussel shell morphology differs between shallow and deep habitats, functional causes and consequences of such difference are unknown. We examined whether quagga mussel shell morphology could be induced by three environmental variables through developmental plasticity. We predicted that shallow-water conditions (high temperature, food quantity, water motion) would yield a morphotype typical of wild quagga mussels from shallow habitats, while deep-water conditions (low temperature, food quantity, water motion) would yield a morphotype present in deep habitats. We tested this prediction by examining shell morphology and growth rate of quagga mussels collected from shallow and deep habitats and reared under common-garden treatments that manipulated the three variables. Shell morphology was quantified using the polar moment of inertia. Of the variables tested, temperature had the greatest effect on shell morphology. Higher temperature (approximately 18-20 degrees C) yielded a morphotype typical of wild shallow mussels regardless of the levels of food quantity or water motion. In contrast, lower temperature (approximately 6-8 degrees C) yielded a morphotype approaching that of wild deep mussels. If shell morphology has functional consequences in particular habitats, a plastic response might confer quagga mussels with a greater ability than zebra mussels to colonize a wider range of habitats within the Great Lakes.

Habitat Reconstruction of Oligocene Elasmobranchs from Yamaga Formation, Ashiya Group, Western Japan

Remains of 11 species of extinct elasmobranch were obtained from the Oligocene Yamaga Formation on Ainoshima Island in northern Kitakyushu City, Japan. More than 360 gill rakers belonging to a basking shark (Cetorhinus sp.) individual were collected from a stratigraphic horizon in the northern part of the island. This report represents the highest concentration of basking shark gill rakers in the fossil record of Japan.Based on sedimentary facies analysis combined with habitat data of extant sharks, habitats of Oligocene elasmobranchs were reconstructed. The result indicates that Oligocene sharks probably lived in an environment similar to that of extant sharks at the genus level. This does not support the previous hypotheses that some shark taxa (e.g., Hexanchus) existed within shallow environments during the Oligocene, and have since migrated into deeper water habitats. Analysis of other genera supports this hypothesis of stability in elasmobranch habitat preference, at least at the genus level, between the Oligocene and present day.

Diet and dietary selectivity of the platypus in relation to season, sex and macroinvertebrate assemblages

The diet of the platypus Ornithorhynchus anatinus was studied by examination of material collected from the cheek pouches of animals captured while foraging in streams in Kangaroo Valley, NSW, Australia. Platypuses consumed benthic invertebrates from 55 families in 16 orders, with virtually no prey being derived from the terrestrial environment. We also sampled invertebrates in pool, riffle and stream edge habitats to identify where prey were obtained. Invertebrates in the diet were most similar to those collected along stream edges and in pools compared with the faster-flowing riffles, suggesting that platypuses focused their foraging activities largely in these deeper water habitats. Although there was no seasonality in the assemblage structure of macroinvertebrates, the diet of platypuses varied between seasons, notably between winter and summer, suggesting that some dietary selectivity is seasonal. Dietary differences between the sexes were not detected. Overall, our results suggest that some dietary selection occurs in the platypus with respect to both foraging habitat and season. Seasonal selectivity may reflect different metabolic demands on platypuses at different times of the year. In contrast, habitat selectivity may reflect difficulty of prey access and risk of prey escape in fast-flowing riffles, higher energy costs and risk of predation associated with exploiting this habitat, and prey avoidance responses that are more rapid in the shallow riffles than in the deeper water pools and stream edges. These alternatives await evaluation by future research.

Size-class partitioning and herding in a foraging group of green turtles Chelonia mydas

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 9:105-116 (2010) - DOI: https://doi.org/10.3354/esr00245 Size-class partitioning and herding in a foraging group of green turtles Chelonia mydas Michael J. Bresette1,*, Blair E. Witherington2, Richard M. Herren1, Dean A. Bagley1, Jonathan C. Gorham1, Steve L. Traxler1, Carrie K. Crady1, Robert Hardy3 1Inwater Research Group Inc., 4160 NE Hyline Dr., Jensen Beach, Florida 34957, USA 2Florida Fish and Wildlife Research Institute, FWC, 9700 South A1A, Melbourne Beach, Florida 32951, USA 3Florida Fish and Wildlife Research Institute, FWC, 100 Eighth Avenue SE, St. Petersburg, Florida 33701, USA *Email: mbresette@inwater.org ABSTRACT: To collect data on green turtles Chelonia mydas near the Marquesas Keys, Florida, USA, we conducted haphazard, unmarked, nonlinear transect (HUNT) surveys from a moving vessel. During HUNTs, we recorded green turtle locations and made opportunistic captures. We found a unique foraging assemblage of subadult and adult green turtles in open-water seagrass habitat (3 to 5 m deep) at the eastern Quicksands, west of the Marquesas Keys. At an adjacent area in the Marquesas Keys (Mooney Harbor), we observed juvenile green turtles foraging in shallow seagrass habitat (<2 m). During 267 km of HUNTs, 370 green turtles (153 adults, 216 subadults, 1 juvenile) were recorded from the eastern Quicksands. At the Mooney Harbor site, 190 juvenile green turtles were sighted during 309 km of transects. Green turtles captured at the eastern Quicksands were adult and subadult animals that ranged from 69.3 to 108.5 cm straight carapace length (SCL; mean ± SD = 88.4 ± 10.6 cm, n = 31). Green turtles captured in Mooney Harbor were juveniles ranging from 27.0 to 59.3 cm SCL (mean = 44.0 ± 7.8, n = 41). Six repeatable, linear transects were surveyed during 3 sampling events at the eastern Quicksands. During these transects, 238 green turtles were observed. These spatial data were used in a nearest-neighbor analysis, which indicated that the distribution of green turtles at the eastern Quicksands was non-random and clumped. We hypothesize that adult and large subadult green turtles use deeper water habitats than juveniles, and this size-class partitioning may be due to differing habitat requirements and predation risk. Our analyses indicate that green turtles found at the eastern Quicksands form foraging herds. KEY WORDS: Green turtle · Foraging ground · Partitioning Full text in pdf format PreviousNextCite this article as: Bresette MJ, Witherington BE, Herren RM, Bagley DA and others (2010) Size-class partitioning and herding in a foraging group of green turtles Chelonia mydas. Endang Species Res 9:105-116. https://doi.org/10.3354/esr00245Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 9, No. 2. Online publication date: January 11, 2010 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2010 Inter-Research.

On the use of the HUGIN 1000 HUS Autonomous Underwater Vehicle for high resolution zooplankton measurements

This paper evaluates and tests the HUGIN 1000 HUS AUV as a carrier platform for the Laser Optical Plankton Counter (LOPC). The LOPC was mounted outside on top of the carrier platform, and the tests confirm that this concept did not create turbulence and zooplankton avoidance.A negligible velocity difference between the flow passing through the sampling tube and the AUV speed was detected. The abundance recorded by the LOPC onboard HUGIN 1000 HUS was within the same order of magnitude compared to the zooplankton abundance from traditional net-based measurements. The results showed zooplankton abundance in the range of 70 to 180 individuals m-3, while other, traditional netbased measurements have indicated 27–332 individuals m-3 from the same area and same depth layer. Note that these numbers are minimum and maximum values observed from a vast number of samples.The mean is approximately 200 individuals m-3. The results provide new and unique high-resolution biological data of deep-water copepod communities. The application of AUVs in marine ecological research introduces advanced methodology with potential to address new scientific questions in deep water habitats.

Plant adaptations and microbial processes in wetlands

Wetlands are terrestrial ecosystems characterized by high and fluctuating water tables. The spatial and temporal differences in the degree to which wetland soils are waterlogged create a very dynamic soil environment with, on average, lower oxygen concentrations than unsaturated soils. Wetland soils are characterized by gradients in redox conditions from totally oxidized to extremely reduced. These conditions require special adaptations for the plant and microbial species in the wetland. Wetland plants, particularly in wetlands with strongly fluctuating water tables, need adaptations to the shortage of oxygen in the root zone, but also to extended periods of dry conditions during low-water phases. Microbial communities are strongly coupled to redox cycles, in which alternative electron acceptors are used, for example nitrate, iron, manganese, sulphate and carbon dioxide. Plant–microbe interactions add to the complexity of the functioning of the wetland soil system. This Highlight section of Annals of Botany addresses the adaptations of plants and microbes in wetlands with fluctuating water levels, following a broad perspective. It contains three review papers and three primary scientific papers with experiments and field comparisons. The review by Parolin et al. gives an overview of adaptations of wetland plants in Amazonian floodplains to drought. The annual water cycle in these wetlands is quite predictable but shows an amplitude of 8 m, giving rise to a long flooded period as well as a long dry period each year. Previously, most emphasis in the evaluation of plant adaptations in these environments had been on the wet phase, focusing on the difficulty of overcoming long periods of waterlogged soil and (partial) submergence of the above-ground parts of plants. This paper for the first time evaluates plant adaptations to the dry period, in the context of the total annual cycle. The review paper by Laanbroek investigates how methane emission from wetland systems is controlled by microbial processes and influenced by wetland vegetation. The complex coupling of the various microbially mediated redox cycles, the leakage of oxygen from the internal plant gas system and the ‘escape’ of methane through this gas system to the atmosphere are evaluated. The review by Verhoeven and Setter deals with human control of water levels in wetlands to promote agricultural use. The emphasis is on the difference between sustainable and non-sustainable uses of wetlands for agriculture. Drainage of peatlands has led to severe soil subsidence and greenhouse gas emissions, whereas floodplains and rice fields are suitable for a more sustainable agricultural use. Developments in crop science, leading to increasingly waterlogging-tolerant crops are also discussed in this context. The paper by Sorrell and Hawes evaluates the importance of convective gas flow in the lacunae of helophytes for the occupation of relatively deep-water habitats. In their study, plant species lacking convective flow occurred in very shallow water only, whereas species with high rates of convective flow were able to grow in deep water, even in eutrophic habitats where the organic soil has a high oxygen demand. Li et al. carried out an experiment with Typha domingensis to test the ability of this species to grow in nutrient-rich, strongly reduced sediments. Growth was adversely affected by low redox potentials, but high availability of phosphates moderated this negative effect. The results are discussed in the context of competitive replacement of Cladium jamaicense by Typha domingensis in parts of the Everglades affected by high agricultural run-off. Finally, Yu and Ehrenfeld have studied the way in which the plant and microbe community structure was affected by water-level fluctuations and soil characteristics in New England forested wetlands. Both median level and variability in water tables turned out to affect plant and microbe communities; however, soil genesis, a result of both water-table position and geologic history, appeared to be even more important.

Vessel noise effects on delphinid communication

Increasing numbers and speeds of vessels in areas with populations of cetaceans may have the cumulative effect of reducing habitat quality by increasing the underwater noise level. Here, we first use digital acoustic tags to demonstrate that free-ranging delphinids in a coastal deep- water habitat are subjected to varying and occasionally intense levels of vessel noise. Vessel noise and sound propagation measurements from a shallow-water habitat are then used to model the potential impact of high sound levels from small vessels on delphinid communication in both shallow and deep habitats, with bottlenose dolphins Tursiops sp. and short-finned pilot whales Globicephala macrorhynchus as model organisms. We find that small vessels travelling at 5 knots in shallow water can reduce the communication range of bottlenose dolphins within 50 m by 26%. Pilot whales in a quieter deep-water habitat could suffer a reduction in their communication range of 58% caused by a vessel at similar range and speed. Increased cavitation noise at higher speeds drastically increases the impact on the communication range. Gear shifts generate high-level transient sounds (peak- peak source levels of up to 200 dB re 1 µPa) that may be audible over many kilometres and may dis- turb close-range animals. We conclude that noise from small vessels can significantly mask acousti- cally mediated communication in delphinids and contribute to the documented negative impacts on animal fitness.

Movements of satellite-tagged Blainville’s beaked whales off the island of Hawai‘i

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 10:203-213 (2009) - DOI: https://doi.org/10.3354/esr00229 Movements of satellite-tagged Blainville’s beaked whales off the island of Hawai‘i Gregory S. Schorr1,*, Robin W. Baird1, M. Bradley Hanson2, Daniel L. Webster1, Daniel J. McSweeney3, Russel D. Andrews4,5 1Cascadia Research Collective, 218 1⁄2 W. 4th Avenue, Olympia, Washington 98501, USA 2NOAA, Northwest Fisheries Science Center, 2725 Montlake Blvd E., Seattle, Washington 98112, USA 3Wild Whale Research Foundation, Box 139, Holualoa, Hawai‘i 96725, USA 4School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska 99709, USA 5Alaska SeaLife Center, 301 Railway Ave., Seward, Alaska 99664, USA *Email: gschorr@cascadiaresearch.org ABSTRACT: Studies of movement patterns and habitat use in cetaceans are often constrained by factors such as ship time, logistics, and the ability to follow individuals over time. Obtaining this information on beaked whales is especially difficult, yet the information is critical to their management and conservation, particularly in light of their susceptibility to naval sonar. To better understand the movements of beaked whales around Hawai‘i, Argos-linked satellite tags were remotely applied to the dorsal fins of 8 Blainville’s beaked whales Mesoplodon densirostris in 2006 and 2008, representing the first time that beaked whales have been tracked by satellite. Transmissions from the tags were received for 15 to 71 d (mean = 48 d). All 8 individuals were tagged west of the island of Hawai‘i, and moved out of the small-boat survey area, also making forays into naval training areas. Despite cumulative straight-line distances moved of up to 2383 km, maximum displacement from tagging location for any individual was only 139 km. Individuals utilized slope waters (mean depth = 1156 m) and remained relatively close to the island (mean distance = 16.9 km). No movements to the east side of the island were documented, despite the availability of similar deep-water habitat. Overall movement patterns suggest that the population is island associated and that individuals exhibit strong site fidelity, both of which increase the susceptibility of this small population to local perturbations. KEY WORDS: Beaked whale · Mesoplodon densirostris · Argos · Satellite tracking · Mid-frequency active sonar · Site fidelity Full text in pdf format Supplementary material PreviousNextCite this article as: Schorr GS, Baird RW, Hanson MB, Webster DL, McSweeney DJ, Andrews RD (2009) Movements of satellite-tagged Blainville’s beaked whales off the island of Hawai‘i. Endang Species Res 10:203-213. https://doi.org/10.3354/esr00229Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 10. Online publication date: November 06, 2009 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2009 Inter-Research.

A new genus and two new species of mesobenthic octopuses from Australia and New Caledonia

Trawl surveys off Western Australia and seamounts south of New Caledonia at depths between 375 and 545 m have yielded two species of a previously unknown genus of benthic octopus (Family: Octopodidae). Histoctopus n. gen. is described here and contains two new species, Histoctopus discus and Histoctopus zipkasae n. spp. The most distinctive morphological feature of this new genus is extreme web margin development along the length of the arms, widening towards the distal tips. Of all benthic octopuses, such web margin development only occurs in this new genus and three other distinct genera, Graneledone, Pteroctopus and Velodona (from comparable depths, typically .200 m). Due to significant morphological differences between these two genera and Histoctopus, we propose that the shared web margin development reflects convergence that is peculiar to a deeper-water habitat. The function of these web extensions remains unknown; they may aid in ensnaring or enveloping prey and/or provide lift while jet swimming off the seafloor.

Can poor foraging habitat (an inundated opencast sulphur mine) be attractive to the great crested grebe (Podiceps cristatus)?

Can poor foraging habitat (an inundated opencast sulphur mine) be attractive to the great crested grebe (Podiceps cristatus)? During investigations of an inundated opencast sulphur mine (an open, deep water habitat with a relatively small littoral area) only five species of breeding water birds were recorded. The density of breeding great crested grebes Podiceps cristatus was relatively high (c. 1.0-1.1 pairs 10 ha-1 of water, and 1.6-1.8 pairs ha-1 of the macrophyte area) although fish density was very low. High water transparency probably compensated for low prey density, because potential prey could be readily detected. Most of the fish were small and occurred in the upper layers of the water column (they could not live below 10 m where the water was anoxic), so were readily available and easily caught by the grebes.

PSEUDOCODIUM MUCRONATUM, A NEW SPECIES FROM NEW CALEDONIA, AND AN ANALYSIS OF THE EVOLUTION OF CLIMATIC PREFERENCES IN THE GENUS (BRYOPSIDALES, CHLOROPHYTA)(1).

A new species, Pseudocodium mucronatum, is described from the Chesterfield platform off the west coast of New Caledonia. The species differs from its congeners in having mucronate utricules. A phylogenetic analysis of rbcL and tufA sequences showed that P. mucronatum is most closely associated with P. natalense De Clerck, Coppejans et Verbruggen and P. devriesii Weber Bosse, with which it shares compressed axes, depressed apices, and plastids in the utricles and the medullar siphons. We studied the evolution of climatic and ecological preferences in the genus using an interdisciplinary approach consisting of relaxed molecular clock analysis, extraction of macroecological data from satellite imagery in a geographic information system (GIS) framework, and ancestral character state estimation. It was shown that the genus originated in tropical waters during the Early Mesozoic. Whereas the P. floridanum-okinawense lineage remained tropical, the lineage including P. natalense, P. devriesii, and P. mucronatum gradually invaded more temperate waters during Cenozoic times. Except for P. devriesii, which occurs in shallow and intertidal habitats, all Pseudocodium species grow in deep-water habitats, and this ecological preference appears to be ancestral.

Measurement and visual verification of fish target strength using an acoustic-optical system attached to a trawlnet

Abstract Ryan, T. E., Kloser, R. J., and Macaulay, G. J. 2009. Measurement and visual verification of fish target strength using an acoustic-optical system attached to a trawlnet. – ICES Journal of Marine Science, 66: 1238–1244. It is difficult to make acoustic target-strength (TS) measurements of fish behaving naturally in deep-water habitats. The fish may avoid the acoustic instrumentation, and, if measured, there is uncertainty about their species and their orientation relative to the incident sound. To address these issues, a novel acoustic-optical system (AOS) has been developed, which combines a battery-powered, dual-frequency, split-beam acoustic system with a low-light video camera. The AOS attaches to the headline of a commercial deep-water demersal trawlnet that herds fish past the AOS and to the codend. This paper describes initial trials of the AOS to measure calibrated TS of New Zealand orange roughy, validated with video images. The fish species were visually identified, and their behaviour and orientation were approximated. The trawl catch provided associated samples for species identification and measurements of their length and other biological metrics. The combination of acoustics and optics in a net-mountable system constitutes a powerful sampling tool with broader applications in fishery research and ecosystem investigations.

Transequatorial Migrations by Basking Sharks in the Western Atlantic Ocean

The world's second largest fish, the basking shark (Cetorhinus maximus), is broadly distributed in boreal to warm temperate latitudes of the Atlantic and Pacific oceans from shallow coastal waters to the open ocean. Previous satellite archival tagging in the North Atlantic has shown that basking sharks move seasonally, are often associated with productive frontal zones, and may make occasional dives to mesopelagic depths. However, basking sharks are thought to be restricted to temperate latitudes, and the extent to which they exploit deeper-water habitat remains enigmatic. Via satellite archival tags and a novel geolocation technique, we demonstrate here that basking sharks are seasonal migrants to mesopelagic tropical waters. Tagged sharks moved from temperate feeding areas off the coast of southern New England to the Bahamas, the Caribbean Sea, and onward to the coast of South America and into the Southern Hemisphere. When in these areas, basking sharks descended to mesopelagic depths and in some cases remained there for weeks to months at a time. Our results demonstrate that tropical waters are not a barrier to migratory connectivity for basking shark populations and highlight the need for global conservation efforts throughout the species range.

Depth distribution of three Typha species, Typha orientalis Presl, Typha angustifolia L. and Typha latifolia L., in an artificial pond

AbstractThe depth distribution of the aquatic macrophyte Typha orientalis Presl was examined in comparison with two other Typha species: Typha angustifolia L. and Typha latifolia L. Vegetation surveys mapping the depth distributions were conducted at Ushigafuchi Pond, Tokyo, Japan, in autumn 2004 and 2005. All vegetation had been cleared from this artificial pond in spring 2003. In 2004 T. orientalis was distributed in shallow to deep water habitats between T. latifolia (shallow water regions) and T. angustifolia (shallow to deep water regions). However, by 2005 T. orientalis had almost disappeared from the pond. It had been replaced by Leersia japonica Makino at depths of 0–30 cm, by Schoenoplectus validus (Vahl) at depths of 30–60 cm and by T. angustifolia at depths of 60–100 cm. It appears that T. orientalis is not a strong competitor, particularly with taller species, but rather a pioneer species.

Results from the European Deep Ocean Margins Research Training Network

Ocean margins mark the transition zones between continents and oceans, where the bulk of sediments are deposited and 50% of marine productivity takes place. The coastal ocean has always been vital for humankind in terms of exploitation of resources, as well as commerce and communication. It has been mainly during the last decade when economic and political interest (e.g., for hydrocarbon search, fisheries and seafloor usage) has spread into deeper waters beyond the shelf break to the continental slope and rise—a zone we herein refer to as the ‘‘Deep Ocean Margin’’ (DOM). Ocean margins are also of great scientific value: scientists study them to understand global climate, sea-level changes, biogeochemical cycles and the flux of fluids from the lithosphere to the ocean and, eventually, to the atmosphere. The recognition of the widespread occurrence of submarine landslides and the discovery of cold-water corals and associated communities are just two examples that illustrate the dynamic nature of the DOM and the scientific and technical challenges they pose. Understanding the mechanisms, architecture, and consequences of submarine landslides is of great importance due to the increasing interest for natural resources in DOM areas, to the geological contribution that landslides make in shaping ocean margins, and to the potential of landslides to trigger large tsunamis that would impact coastal areas (Locat and Mienert 2003; Canals et al. 2004; Lykousis et al. 2007). Cold-water corals illustrate the variability and diversity of Earth’s ecosystems and also the limitations of our knowledge on DOMs. Cold-water corals are not only a unique ecosystem that has been seriously damaged in many areas because of trawling activities, but also a refuge and breeding place for many marine species, including some of commercial interest, and a potential source for biosubstances of pharmaceutical interest. While their distribution along the European margins is now rather well known, a sound comprehension of their occurrence is essential in order to understand biological activity and related geological processes, and to permit sustainable resource exploitation and effective preservation of these deep-water habitats (Roberts et al. 2006; Freiwald and Roberts 2005; UNEP 2007).

Leptofauchea coralligena (Faucheaceae, Rhodophyta), a new species from the Mediterranean Sea

Morphological and reproductive studies, corroborated by gene sequence data, demonstrate that there are two distinct entities within Mediterranean specimens referable to the red alga Rhodymenia ardissonei (Rhodymeniaceae). Genuine R. ardissonei grows in shallow water while specimens from deep water habitats, traditionally attributed to the same species, belong to Leptofauchea, a genus placed in the Faucheaceae. The deep water growth is herein described as a new species, Leptofauchea coralligena. Female gametophytes in Leptofauchea are easily distinguished because of the presence of a tela arachnoidea in the pericarp cavity and tetrasporangia developing in nemathecia. Sterile specimens, however, can be extremely difficult to tell apart because differences in vegetative morphology and anatomy are subtle. Refractive bodies in the medullary cells form the most conspicuous diagnostic character separating L. coralligena from R. ardissonei. These structures can be easily observed in young specimens of L. coralligena, both in surface view and transverse sections. However this character becomes less obvious or even impossible to observe in mature thalli with medullary cells containing large amounts of floridean starch. Refractive bodies are also difficult to observe in herbarium specimens. The existence of these structures has not previously been reported from any other Leptofauchea species. The presence of L. coralligena has been confirmed in the western Mediterranean Sea. Atlantic specimens attributed to R. ardissonei require further study.

Age Estimates of Two Large Misty Grouper, Epinephelus mystacinus (Serranidae) from Bermuda with a Comparison of the Age of Tropical Groupers in the Western Atlantic

Misty grouper are known to attain at least 54 kg and 115 cm total length (TL) (Heemstra and Randall 1993) although a maximum size of 160 cm TL is reported (Appeldoorn et al. 1987, cited in www.FishBase.com). Recently, two specimens (152 and 157 mm TL) were landed by commercial fisherman from the edge of the Bermuda platform, providing documentation of the maximum size which may be attained by this species. There are no age and growth studies on misty grouper (Heemstra and Randall 1993; www.FishBase.com). Therefore, the age data presented here, although not validated, represent the first estimates of maximum longevity and support Campana’s (2005) statement that, “methods for validating ages of deep-sea fishes are urgently required.” We compared the age estimates of our misty grouper specimens with the age of a large wreckfish (45.5 kg) taken from a similar but deeper-water habitat. In addition, we provide a comparison of the maximum ages of 9 other species of grouper in the western Atlantic.

Reproductive strategies in female polar and deep-sea bobtail squid genera Rossia and Neorossia (Cephalopoda: Sepiolidae)

Female reproductive features have been investigated in five polar and deep-sea bobtail squid genera Rossia and Neorossia (R. macrosoma, R. moelleri, R. pacifica, N.c. caroli and N.c. jeannae). These species are characterized by asynchronous ovary maturation, very large eggs (>10% ML), fecundity of several hundred oocytes, very high reproductive output, and continuous spawning with low batch fecundity. This adaptive complex of reproductive traits evolved in these small animals as an optimum strategy for polar and deep-water habitats.