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Zirino, A, Elwany H, Neira C, Maicu F, Mendoza G, Levin LA.  2014.  Salinity and its variability in the Lagoon of Venice, 2000–2009. Advances in Oceanography and Limnology. 5:41-59.: Taylor & Francis   10.1080/19475721.2014.900113   Abstract

Yearly averages computed from monthly and bimonthly salinity data collected between 2000 and 2009 from 13 broadly spaced stations in the Venice Lagoon were analysed in view of 30 min data collected semi-continuously during 2009 at nine similarly located stations. Data from all stations and all years indicate that, based on yearly averages, the lagoon may be divided along its major (long) axis into three areas: 1) a northern, freshwater impacted area (S = <28 PSU) of high, tidally-caused, variability, 2) a southern, marine, zone of S >32 PSU of low, tidally-caused, variability, and 3) an intermediate zone. Salinity changes are closely associated with rainfall events, and the incoming freshwater is consistently distributed throughout the lagoon by tidal action. Much variability is simply a result of the forward and backward motion of the tides and is not caused by a salinity change in the water itself. The consistency of the 2000?2009 data and the historical (to 1961) watershed record support the hypothesis that the Venice Lagoon has been and is currently at steady-state with respect to its salinity distribution. As such, it is conducive to the development of (at least) three separate ecosystems.

Blair, NE, Levin LA, Demaster DJ, Plaia G.  1996.  The short-term fate of fresh algal carbon in continental slope sediments. Limnology and Oceanography. 41:1208-1219. AbstractWebsite

Emplacement of a tracer mixture containing C-13-labeled green algae on the sea floor of the continental slope offshore of Cape Hatteras, North Carolina, elicited a rapid response over 1.5 d from the dense benthic community. Certain deposit-feeding annelids (e.g. Scalibregma inflatum and Aricidea quadrilobata) became heavily labeled with C-13 as a result Of ingestion of the algae. C-13-labeled organic matter was transported to a depth of at least 4-5 cm into the seabed during the 1.5-d period, presumably as a consequence of a feeding-associated activity. Nonlocal transport produced subsurface peaks in organic C-13 at 2-3 cm. Dissolved inorganic C-13, produced by the oxidation of the labeled algae, penetrated to 10-cm depth. The transport of highly reactive organic matter from the sediment surface at initial velocities greater than or equal to 3 cm d(-1) is expected to be an important control of subsurface benthic processes in slope environments characterized by abundant macrofaunal populations. Anaerobic processes, which are enhanced on the Cape Hatteras slope relative to adjacent areas, may be promoted by the rapid injection of reactive material into subsurface sediments. The transport, in turn, is a consequence of the dense infaunal populations that are supported by the rapid deposition of organic carbon in this region.

Woulds, C, Andersson JH, Cowie GL, Middelburg JJ, Levin LA.  2009.  The short-term fate of organic carbon in marine sediments: Comparing the Pakistan margin to other regions. Deep Sea Research (Part II, Topical Studies in Oceanography). 56:393-402., United Kingdom: Elsevier BV   10.1016/j.dsr2.2008.10.008   AbstractWebsite

Pulse-chase experiments with isotopically labelled phytodetritus conducted across the Pakistan margin reveal that the impact of biological activities on benthic C-cycling varies markedly among sites exhibiting different seafloor conditions. In this study, patterns of biological C-processing across the Pakistan margin oxygen minimum zone (OMZ) are compared with those observed in previous tracer studies. Variations in site environmental conditions are proposed to explain the considerable variations in C-processing patterns among this and previous studies. Three categories of C-processing pattern are identified: (1) respiration dominated, where respiration accounts for >75% of biological C-processing, and uptake by metazoan macrofauna, foraminifera and bacteria are relatively minor processes. These sites tend to show several (although not necessarily all) of the properties of being cold and deep, and having low inputs of organic carbon to the sediment and relatively low-biomass metazoan macrofaunal communities; (2) active faunal uptake, where respiration accounts for <75%, and metazoan macrofaunal, foraminiferal and bacterial uptake each account for 10-25% of biological C-processing. This type is further split into metazoan macrofaunal- and foraminiferal-dominated situations, dictated by oxygen availability; and (3) metazoan macrofaunal uptake dominated, characterised by metazoan macrofaunal uptake accounting for ~50% of biological C-processing, due to unusually large biomasses of the phytodetritus-consuming animals. Total respiration rates (of added C) on the Pakistan margin fell within the range of rates measured elsewhere in the deep sea (} .1-2.8mgCm super(-) super(2)h super(-) super(1)), and seem to be dominantly controlled by seafloor temperature. Rates of metazoan macrofaunal uptake of organic matter (OM) on the Pakistan margin are larger than those in most other studies, and this is attributed to the large and active metazoan macrofaunal communities in the lower OMZ, characteristic of OMZ boundaries. Finally, biological mixing of Pakistan margin sediments was reduced compared to that observed in comparable tracer studies on other margins. This probably reflects faunal feeding and burrowing strategies consistent with low oxygen concentrations and a relatively abundant supply of sedimentary OM.

Andersson, JH, Woulds C, Schwartz M, Cowie GL, Levin LA, Soetaert K, Middelburg JJ.  2008.  Short-term fate of phytodetritus in sediments across the Arabian Sea oxygen minimum zone. Biogeosciences. 5:43-53. AbstractWebsite

The short-term fate of phytodetritus was investigated across the Pakistan margin of the Arabian Sea at water depths ranging from 140 to 1850 m, encompassing the oxygen minimum zone (similar to 100-1100 m). Phytodetritus sedimentation events were simulated by adding similar to 44 mmol (13)C-labelled algal material per m(2) to surface sediments in retrieved cores. Cores were incubated in the dark, at in situ temperature and oxygen concentrations. Overlying waters were sampled periodically, and cores were recovered and sampled (for organisms and sediments) after durations of two and five days. The labelled carbon was subsequently traced into bacterial lipids, foraminiferan and macrofaunal biomass, and dissolved organic and inorganic pools. The majority of the label (20 to 100%) was in most cases left unprocessed in the sediment at the surface. The largest pool of processed carbon was found to be respiration (0 to 25% of added carbon), recovered as dissolved inorganic carbon. Both temperature and oxygen were found to influence the rate of respiration. Macrofaunal influence was most pronounced at the lower part of the oxygen minimum zone where it contributed 11% to the processing of phytodetritus.

Mehring, AS, Hatt BE, Kraikittikun D, Orelo BD, Rippy MA, Grant SB, Gonzalez JP, Jiang SC, Ambrose RF, Levin LA.  2016.  Soil invertebrates in Australian rain gardens and their potential roles in storage and processing of nitrogen. Ecological Engineering. 97:138-143.   10.1016/j.ecoleng.2016.09.005   AbstractWebsite

Research on rain gardens generally focuses on hydrology, geochemistry, and vegetation. The role of soil invertebrates has largely been overlooked, despite their well-known impacts on soil nutrient storage, removal, and processing. Surveys of three rain gardens in Melbourne, Australia, revealed a soil invertebrate community structure that differed significantly among sites but was stable across sampling dates (July 2013 and April 2014). Megadrilacea (earthworms), Enchytraeidae (potworms), and Collembola (springtails) were abundant in all sites, and together accounted for a median of 80% of total soil invertebrate abundance. Earthworms were positively correlated to soil organic matter content, but the abundances of other taxonomic groups were not strongly related to organic matter content, plant cover, or root biomass across sites. While less than 5% of total soil N was estimated to be stored in the body tissues of these three taxa, and estimated N gas emissions from earthworms (N2O and N-2) were low, ingestion and processing of soil was high (e.g., up to 417% of the upper 5 cm of soil ingested by earthworms annually in one site), suggesting that the contribution of these organisms to N cycling in rain gardens may be substantial. Thus, invertebrate communities represent an overlooked feature of rain garden design that can play an important role in the structure and function of these systems. (C) 2016 Elsevier B.V. All rights reserved.

Becker, BJ, Fodrie FJ, McMillan PA, Levin LA.  2005.  Spatial and temporal variation in trace elemental fingerprints of mytilid mussel shells: A precursor to invertebrate larval tracking. Limnology and Oceanography. 50:48-61. AbstractWebsite

Elements incorporated into developing hard parts of planktonic larvae record the environmental conditions experienced during growth. These chemical signatures, termed elemental fingerprints, potentially allow for reconstruction of locations of larvae. Here, we have demonstrated for the first time the feasibility of this approach for bivalve shells. We have determined the spatial scale over which we are able to discriminate chemical signatures in mussels in southern California and characterized the temporal stability of these signals. Early settlers of Mytilus californianus and Mytilus galloprovincialis were collected from eight sites in southern California. Shells were analyzed for nine isotopes using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). We discriminated among mussels collected in two bays and the open coast using Mn, Pb, and Ba shell concentrations. Shell concentrations of Pb and Sr were sufficiently different to discriminate between mussels from the northern and southern regions of the open coast, each representing approximately 20 km of coastline. These signals were relatively stable on monthly and weekly time scales. These results indicate that trace elemental fingerprinting of shell material is a promising technique to track bivalve larvae moving between bays and the open coast or over along-shore scales on the order of 20 km. Identification of spatial variation in elemental fingerprints that is stable over time represents a crucial step in enhancing our ability to understand larval transport and population connectivity in invertebrates.

Neira, C, Delgadillo-Hinojosa F, Zirino A, Mendoza G, Levin LA, Porrachia M, Deheyn DD.  2009.  Spatial distribution of copper in relation to recreational boating in a California shallow-water basin. Chemistry and Ecology. 25:417-433.   10.1080/02757540903334197   AbstractWebsite

The overall effect of the number of boats on the copper (Cu) levels in the water column and sediment, along with their spatial variability within Shelter Island Yacht Basin (SIYB), San Diego Bay, California was examined. We identified a horizontal gradient of increasing dissolved Cu and Cu in sediment from outside to the head of SIYB which was coincident with the increasing number of boats. Spatial models of Cu distribution in water and sediment indicated the presence of 'hotspots' of Cu concentration. From outside to the head of SIYB, dissolved Cu ranged from 1.3 gL-1 to 14.6 gL-1 in surface water, and 2.0 gL-1 to 10.2 gL-1 in bottom water. Cu in sediment exceeded the Effect Range Low of 34mgkg-1 (i.e. where adverse effects to fauna may occur), with a peak concentration of 442mgkg-1 at the head of the basin. Free Cu++ in surface water was several orders of magnitude higher than in sediment porewater. High-resolution data of Cu species together with probability maps presented in this paper will allow managers to easily visualise and localise areas of impaired quality and to prioritise which areas should be targeted to improve Cu-related conditions.

Schaff, TR, Levin LA.  1994.  Spatial heterogeneity of benthos associated with biogenic structures on the North Carolina continental slope. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 41:901-&.   10.1016/0967-0645(94)90053-1   AbstractWebsite

The objective of this study was to determine if biogenic features such as mounds, pits and tubes produce small-scale (0.1-100 m) spatial heterogeneity in macrofaunal community structure on the continental slope off North Carolina at 850 m. Macrofaunal and microbial communities associated with sediment mounds, pits and level areas were compared off Cape Lookout, North Carolina. No significant differences were found in sediment microbial counts or total macrofaunal distributions. One paraonid polychaete (Levensenia gracilis) was more abundant in pits than in the other samples, and infaunal anemones exhibited depressed densities in sediment mounds. At a second site, off Cape Hatteras, North Carolina, infaunal heterogeneity associated with the tube-building foraminiferan Bathysiphon filiformis was examined by comparing an area with high tube densities (93.8 m(-2)) with an area 100 m away without tubes. No significant differences were found in the distribution and abundances of bacteria between the two areas. The only significant difference found in infaunal densities was the presence of high numbers of reproductive oligochaetes in the 5-10 cm fraction beneath tube beds. One terebellid polychaete species (Nicolea sp.), which lives exclusively on B. filiformis tubes, was absent in the non-tube area. With a few exceptions, the biogenic structures examined at these two sites appeared to exert only minor influence on macrofaunal or microbial community structure. Within each site, slope assemblages examined in this study appeared to be homogeneous on the small scales examined.

Schaff, T, Levin L, Blair N, DeMaster D, Pope R, Boehme S.  1992.  Spatial heterogeneity of benthos on the Carolina continental slope: Large (100 km)-scale variation. Marine ecology progress series. Oldendorf. 88:143-160. AbstractWebsite

Large-scale spatial heterogeneity of macrofaunal and microbial communities was examined on the continental slope off North and South Carolina, USA, by comparing 3 sites, separated by 130 to 150 km and all at 850 m water depth. Significant variation was found among macrofaunal assemblages at all 3 sites, and between microbial counts at 2 sites. We investigated the hypothesis that 100 km scale heterogeneity was driven by variation in organic C flux to the sea floor. The northernmost site (Site III, off Cape Hatteras, NC) was found to have macrofaunal abundances (> 55,000 m super(-2)) higher than any previously recorded from this depth, and significantly higher than those at Site II (off Cape Lookout, NC) (21,319 m super(-2)) or Site I (off Charleston, SC) (9438 m super(-2)). Trends in macrofaunal abundance did not follow those of sediment TOC (total organic carbon), but agreed well with estimates of total carbon flux for the 3 sites. Mixing coefficients determined from profiles of naturally occurring super(234)Th (half life 24 d) indicate that the sediments at Site III are mixed 2 to 6 times faster than at the other 2 sites, which is consistent with the trends in macrofaunal abundance and biomass.

Levin, LA, Ziebis W, Mendoza GF, Growney VA, Tryon MD, Brown KM, Mahn C, Gieskes JM, Rathburn AE.  2003.  Spatial heterogeneity of macrofauna at northern California methane seeps: influence of sulfide concentration and fluid flow. Marine Ecology-Progress Series. 265:123-139.   10.3354/meps265123   AbstractWebsite

Relationships among fluid flow, sulfide concentration, sulfur bacteria and macrofaunal assemblages were examined at methane seeps on the northern California margin, near the mouth of the Eel River (512 to 525 m). Over a 6 mo period, sediments covered with microbial mats exhibited significant but variable outflow of altered fluids, with no flow reversals. This fluid flow was associated with high porewater sulfide concentrations (up to 20 mM) and almost no oxygen penetration of sediments (<0.1 mm). Vesicomya pacifica (clam) bed and non-seep sediments exhibited little net fluid outflow and similar oxygen penetration (3 and 4 mm, respectively); however, sulfide concentrations were higher in subsurface clam-bed sediments (up to 2 mM) than in non-seep sediments (<200 muM). Macrofaunal densities did not differ among the 3 habitats (13 800 to 16 800 ind. m(-2); >300 mum), but biomass and diversity (no. species per core, E(S-100), H') were lower and composition varied in the sulfidic microbial mat sediments relative to clam-bed and non-seep sediments. The community in microbial mat-covered sediments consisted largely (82%) of 6 species in the polychaete family Dorvilleidae, whereas the clam-bed and non-seep microhabitats supported a mixture of annelids, peracarid crustaceans, nemerteans, and mollusks. Vertical microprofiling of sulfide in animal cores indicated that most taxa avoid H2S concentrations >1 mM. However, sulfide-oxidizing filamentous bacteria, dorvilleid polychaetes and bivalves (mainly V. pacifica) exhibited highest densities at sulfide concentrations of 1 to 5 mM sulfide. Horizontal and vertical patterns of sulfide availability have a strong influence on the fine-scale distribution, structure and composition of macrofaunal assemblages inhabiting methane seeps and must be accounted for when characterizing the microbiology and ecology of seep habitats.

Tegner, MJ, Levin LA.  1983.  Spiny lobsters and sea urchins: Analysis of a predator-prey interaction. Journal of Experimental Marine Biology and Ecology. 73:125-150.   10.1016/0022-0981(83)90079-5   AbstractWebsite

Spiny lobsters, Panulirus interruptus (Randall), are important predators of two species of sea urchins, Strongylocentrotus franciscanus (A. Agassiz) and S. purpuratus (Stimpson), which are major herbivores in southern California kelp forest communities. Aquarium experiments indicate that spiny lobsters strongly prefer S. purpuratus over S. franciscanus of comparable test diameter, probably accounting for the higher number of S. purpuratus mortalities observed in the field. Juvenile S. franciscanus (< 60 mm test diameter, TD) are preferred over larger conspecifics, but the smallest S. franciscanus (< 30 mm TD) are protected by association with the adult urchin spine canopy. Mid-sized S. franciscanus too large to fit under the spine canopy are subject to intense predation. All sizes of P. interruptus tested showed a notable reluctance to attack large S. franciscanus (> 90 mm TD) when offered a range of sizes, although the larger lobsters are capable of handling the largest urchins. Relative movement, spine length, test thickness, and gonad weights of sea urchins were examined to evaluate the factors affecting the lobsters' choice of prey, and behavioral responses to lobsters were assessed to determine urchin availability to these predators. The handling problems associated with the long spines of larger S. franciscanus appear to be the major considerations in prey choice despite the much greater potential energy gain from these urchins. Thus predation by spiny lobsters appears to be sufficient to explain the bimodal size-frequency distribution typical of S. franciscanus populations in areas where these predators are common. Heavy fishing pressure on spiny lobsters during this century probably resulted in the release of sea urchin populations and contributed to episodes of destructive urchin grazing observed in the 1950's and subsequent years.

Thurber, AR, Kroger K, Neira C, Wiklund H, Levin LA.  2010.  Stable isotope signatures and methane use by New Zealand cold seep benthos. Marine Geology. 272:260-269.   10.1016/j.margeo.2009.06.001   AbstractWebsite

The carbon isotopic composition of seep faunal tissue represents a time-integrated view of the interaction between biology and the biogeochemical gradients within the environment. Here we provide an initial description of carbon and nitrogen stable isotope signatures of dominant symbiont-bearing megafauna and heterotrophic mega- and macrofauna from 10 methane-seep sites on the continental margin of the North Island of New Zealand (662-1201 m water depth). Isotopic signatures suggest that sulfide oxidation supports symbiont-bearing taxa including solemyid and vesicomyid bivalves, and methanotrophic symbionts are present in the seep mussel Bathymodiolus sp Multiple species of Frenulata (Siboglinidae) are present and have a range of isotopic values that are indicative of both thiotroph- and methanotroph-based nutrition. Isotopic composition of the tubeworm Lamellibrachia sp. varied by 23 3 parts per thousand among individuals although there was no consistent difference among sites Variation in methane use by heterotrophic fauna appears to reflect the availability of hard vs. soft substrate, macrofauna on hard substrates had high delta(13)C signatures, reflecting consumption of photosynthetic-derived organic matter Two unique, biotic assemblages were discovered to be fueled largely by methane: a hard-substrate, multi-phyla sponge-associated community (inhabiting the sponge Pseudosuberites sp) and a soft-sediment assemblage dominated by ampharetid polychaetes Isotope signatures yield estimates of 38-100% and 6-100% methane-derived carbon in sponge associates and ampharetid-bed macrofauna. respectively. These estimates are comparable to those made for deeper methane seeps at the Florida Escarpment (3290 m) and Kodiak. Alaska seeps (4445 m) The overall high use of methane as a carbon source by both symbiont-bearing and heterotrophic fauna suggests that New Zealand methane seeps are an ideal model system to study the interaction among metazoans, bacteria, archaea, and their resulting effect on methane cycles. (C) 2009 Elsevier B V All rights reserved

Dunn, DC, Vandover CL, Etter RJ, Smith CR, Levin LA, Morato T, Colaco A, Dale AC, Gebruk AV, Gjerde KM, Halpin PN, Howell KL, Johnson D, Perez JAA, Ribeiro MC, Stuckas H, Weaver P, Participants SW.  2018.  A strategy for the conservation of biodiversity on mid-ocean ridges from deep-sea mining. Science Advances. 4   10.1126/sciadv.aar4313   AbstractWebsite

Mineral exploitation has spread from land to shallow coastal waters and is now planned for the offshore, deep seabed. Large seafloor areas are being approved for exploration for seafloor mineral deposits, creating an urgent need for regional environmental management plans. Networks of areas where mining and mining impacts are prohibited are key elements of these plans. We adapt marine reserve design principles to the distinctive biophysical environment of mid-ocean ridges, offer a framework for design and evaluation of these networks to support conservation of benthic ecosystems on mid-ocean ridges, and introduce projected climate-induced changes in the deep sea to the evaluation of reserve design. We enumerate a suite of metrics to measure network performance against conservation targets and network design criteria promulgated by the Convention on Biological Diversity. We apply these metrics to network scenarios on the northern and equatorial Mid-Atlantic Ridge, where contractors are exploring for seafloor massive sulfide (SMS) deposits. A latitudinally distributed network of areas performs well at (i) capturing ecologically important areas and 30 to 50% of the spreading ridge areas, (ii) replicating representative areas, (iii) maintaining along-ridge population connectivity, and (iv) protecting areas potentially less affected by climate-related changes. Critically, the network design is adaptive, allowing for refinement based on new knowledge and the location of mining sites, provided that design principles and conservation targets are maintained. This framework can be applied along the global mid-ocean ridge system as a precautionary measure to protect biodiversity and ecosystem function from impacts of SMS mining.

Parker, ED, Forbes VE, Nielsen SL, Ritter C, Barata C, Baird DJ, Admiraal W, Levin L, Loeschke V, Lyytikainen-Saarenmaa P, Hogh-Jensen H, Calow P, Ripley BJ.  1999.  Stress in ecological systems. Oikos. 86:179-184.   10.2307/3546584   AbstractWebsite
Ramirez-Llodra, E, Trannum HC, Evenset A, Levin LA, Andersson M, Finne TE, Hilario A, Flem B, Christensen G, Schaanning M, Vanreusel A.  2015.  Submarine and deep-sea mine tailing placements: A review of current practices, environmental issues, natural analogs and knowledge gaps in Norway and internationally. Marine Pollution Bulletin. 97:13-35.   10.1016/j.marpolbul.2015.05.062   AbstractWebsite

The mining sector is growing in parallel with societal demands for minerals. One of the most important environmental issues and economic burdens of industrial mining on land is the safe storage of the vast amounts of waste produced. Traditionally, tailings have been stored in land dams, but the lack of land availability, potential risk of dam failure and topography in coastal areas in certain countries results in increasing disposal of tailings into marine systems. This review describes the different submarine tailing disposal methods used in the world in general and in Norway in particular, their impact on the environment (e.g. hyper-sedimentation, toxicity, processes related to changes in grain shape and size, turbidity), current legislation and need for future research. Understanding these impacts on the habitat and biota is essential to assess potential ecosystem changes and to develop best available techniques and robust management plans. (C) 2015 Elsevier Ltd. All rights reserved.

Gallo, ND, Cameron J, Hardy K, Fryer P, Bartlett DH, Levin LA.  2015.  Submersible- and lander-observed community patterns in the Mariana and New Britain trenches: Influence of productivity and depth on epibenthic and scavenging communities. Deep-Sea Research Part I-Oceanographic Research Papers. 99:119-133.   10.1016/j.dsr.2014.12.012   AbstractWebsite

Deep-sea trenches remain one of the least explored ocean ecosystems due to the unique challenges of sampling at great depths. Five submersible dives conducted using the DEEPSEA CHALLENGER submersible generated video of undisturbed deep-sea communities at bathyal (994 m), abyssal (3755 m), and hadal (8228 m) depths in the New Britain Trench, bathyal depths near the Ulithi atoll (1192 m), and hadal depths in the Mariana Trench Challenger Deep (10908 m). The New Britain Trench is overlain by waters with higher net primary productivity (similar to 3-fold) than the Mariana Trench and nearby Ulithi, and receives substantially more allochthonous input from terrestrial sources, based on the presence of terrestrial debris in submersible video footage. Comparisons between trenches addressed how differences in productivity regime influence benthic and demersal deep-sea community structure. In addition, the scavenger community was studied using paired lander deployments to the New Britain (8233 m) and Mariana (10918 m) trenches. Differences in allochthonous input were reflected in epibenthic community abundance, biodiversity, and lifestyle representation. More productive locations were characterized by higher faunal abundances (similar to 2-fold) at both bathyal and hadal depths. In contrast, biodiversity trends showed a unimodal pattern with more food-rich areas exhibiting reduced bathyal diversity and elevated hadal diversity. Hadal scavenging communities exhibited similar higher abundance but also similar to 3-fold higher species richness in the more food-rich New Britain Trench compared to the Mariana Trench. High species- and phylum-level diversity observed in the New Britain Trench suggest that trench environments may foster higher megafaunal biodiversity than surrounding abyssal depths if food is not limiting. However, the absence of fish at our hadal sites suggests that certain groups do have physiological depth limits. Submersible video footage allowed novel in situ observation of holothurian orientation, jellyfish feeding behavior as well as lifestyle preferences for substrate, seafloor and overlying water. This study documents previously unreported species in the New Britain Trench, including an ulmariid scyphozoan (8233 m) and an acrocirrid polychaete (994 m), and reports the first observation of an abundant population of elpidiid holothurians in the Mariana Trench (10908 m). It also provides the first megafaunal community analysis of the world's deepest epibenthic community in the Mariana Trench Challenger Deep, which was composed of elpidiid holothurians, amphipods, and xenophyophores. (C) 2015 The Authors. Published by Elsevier Ltd.

Levin, LA, Talley D, Thayer G.  1996.  Succession of macrobenthos in a created salt marsh. Marine Ecology-Progress Series. 141:67-82.   10.3354/meps141067   AbstractWebsite

Early succession of macrofauna was examined over several years in a created Spartina alterniflora marsh located on the Newport River Estuary, North Carolina, USA. Epifauna and infaunal community structure and composition were compared at 2 elevations in plots planted with S. alterniflora, plots left bare of vegetation and vegetated plots in a nearby natural S, alterniflora marsh. No significant successional differences were observed between vegetated and unvegetated sediments in the created marsh. The earliest stages of colonization involved recruitment by opportunistic estuarine polychaetes: Streblospio benedicti, Capitella spp, and Polydora cornuta. Capitella spp. dominated the macrofauna a month after marsh creation, but thereafter S. benedicti was the most abundant species. During the first few years, the artificial marsh retained early successional characteristics, with S, benedicti, Capitella spp. and turbellarians accounting for 75 to 95% of the total macrofauna. Fiddler crabs were common epifaunal colonists. After 4 yr, species richness increased and dominance by the early colonists diminished. Taxa lacking planktonic larvae and swimming adults were particularly slow to recover in the created marsh, but accounted for over 25% of the infauna by Year 4. Oligochaetes, which comprised over 50% of the fauna in the natural marsh, remained absent or rare in the artificial system throughout the study. Infaunal recovery appears to be more rapid in lower than upper marsh elevations. Although macrofaunal densities and species richness of sediments in the lower created marsh came to resemble those of the natural marsh within 6 mo, species composition and faunal feeding modes did not. These observations suggest there may be significant functional differences between young artificial marshes and older natural marshes. Consideration of the timing of marsh creation, marsh configuration, continuity with natural marshes, seeding of taxa with poor dispersal, and attention to species habitat requirements are recommended to accelerate infaunal colonization of created Spartina marshes.

Janousek, CN, Currin CA, Levin LA.  2007.  Succession of microphytobenthos in a restored coastal wetland. Estuaries and Coasts. 30:265-276. AbstractWebsite

Sediment microphytobenthos, such as diatoms and photosynthetic bacteria, are functionally important components of food webs and are key mediators of nutrient dynamics in marine wetlands. The medium to long-term recovery of benthic microproducers in restored habitats designed to improve degraded coastal wedand sites is largely unknown. Using taxon-specific photopigments, we describe the composition of microphytobenthic communities in a large restoration site in southern California and differences in the temporal recovery of biomass (chlorophyll a), composition, and taxonomic diversity between vegetated Spartina foliosa salt marsh and unvegetated mudflat. Visually distinct, spatially discreet, microphytobenthic patches appeared after no more than 7 mo within the restoration site and were distinguished by significant differences in biomass, taxonomic diversity, and the relative abundance of cyanobacteria versus diatoms. Sediment chlorophyll a concentrations within the restored site were similar to concentrations in nearby natural habitat 0.2-2.2 yr following marsh creation, suggesting rapid colonization by microproducers. Restored Spartina marsh very rapidly (between 0.2 and 1.2 yr) acquired microphytobenthic communities of similar composition and diversity to those in natural Spartina habitat, but restored mudflats took at least 1.6 to 2.2 yr to resemble natural mudflats. These results suggest relatively rapid recovery of microphytobenthic communities at the level of major taxonomic groups. Sediment features, such as pore water salinity and Spartina density, explained little variation in microphytobenthic taxonomic composition. Ile data imply that provision of structural heterogeneity in wedand construction (such as pools and vascular plants) might speed development of microproducer communities, but no direct seeding of sediment microfloras may be necessary.

Robinson, CA, Bernhard JM, Levin LA, Mendoza GF, Blanks JK.  2004.  Surficial hydrocarbon seep infauna from the Blake Ridge (Atlantic Ocean, 2150 m) and the Gulf of Mexico (690-2240 m). Marine Ecology-Pubblicazioni Della Stazione Zoologica Di Napoli I. 25:313-336.   10.1111/j.1439-0485.2004.00034.x   AbstractWebsite

Infauna, including foraminifera and metazoans, were enumerated and identified from five types of seep habitats and two adjacent non-seep habitats. Collections were made with the deep submergence research vessel 'Alvin' from three areas of active seepage in the Gulf of Mexico (Alaminos Canyon [2220 m], Atwater Canyon [1930 m], and Green Canyon lease block 272 [700 m]) and on the Blake Ridge Diapir [2250 m], which is located off the southeastern coast of the United States. The seep habitats sampled included four types of microbial mats (Beggiatoa, Thioploca, thin and thick Arcobacter) and the periphery of a large mussel bed. Sediments under large rhizopod protists, xenophyophores, were sampled adjacent to the mussel bed periphery. A non-seep site, which was >1 km away from active seeps, was also sampled for comparison. Densities of most taxa were higher in the Gulf of Mexico seeps than in Blake Ridge samples, largely because densities in the thick microbial mats of Blake Ridge were significantly lower. Diversity was higher in the Thioploca mats compared to other microbial-mat types. Within an ocean basin (i.e., Atlantic, Gulf of Mexico) we did not observe significant differences in meiofaunal or macrofaunal composition in Beggiatoa versus Thioploca mats or thin versus thick Arcobacter mats. Foraminifera represented up to 16% of the seep community, a proportion that is comparable to their contribution at adjacent non-seep communities. In general, the observed densities and taxonomic composition of seep sites at the genus level was consistent with previous observations from seeps (e.g., the foraminifers Bolivina and Fursenkoina, the dorvilleid polychaete Ophryotrocha).