TAXON DIVERSITY AND COMMUNITY STRUCTURE OF FOSSIL MOLLUSCAN ASSEMBLAGES FROM THE MID-ATLANTIC CONTINENTAL SHELF (USA)

2018 ◽  
Author(s):  
Carmi Milagros Thompson ◽  
◽  
Rowan Lockwood ◽  
E.N. Worthington ◽  
Kelvin W. Ramsey
2011 ◽  
Vol 2 (1) ◽  
pp. 33 ◽  
Author(s):  
Peter A. Lee ◽  
Sarah F. Riseman ◽  
Clinton E. Hare ◽  
David A. Hutchins ◽  
Karine Leblanc ◽  
...  

The potential impact of elevated sea surface temperature (SST) and pCO2 on algal community structure and particulate dimethylsulfoniopropionate (DMSPp) concentrations in the southeastern Bering Sea was examined using a shipboard “Ecostat” continuous culture system. The ecostat system was used to mimic the conditions projected to exist in the world's oceans by the end of this century (i.e. elevated pCO2 (750 ppm) and elevated SST (ambient + 4°C). Two experiments were conducted using natural phytoplankton assemblages from the high-nutrient low-chlorophyll (HNLC) central basin and from the middle domain of the southeastern continental shelf. At the HNLC site, the relative abundances of haptophytes and pelagophytes were higher and the relative abundance of diatoms lower under “greenhouse” conditions (i.e. combined 750 ppm CO2 and elevated temperature) than control conditions (380 ppm CO2 and ambient temperature). This shift in algal community structure was accompanied by increases in DMSPp (2–3 fold), DMSPp:Chl a (2–3 fold) and DMSP:PON (2 fold). At the continental shelf site, the changes in the relative abundances of haptophytes, pelagophytes and diatoms under “greenhouse” conditions were similar to those observed at the HNLC site, with 2.5 fold increases in DMSPp, 50–100% increases in DMSPp:Chl a and 1.8 fold increases in DMSP:PON. At both locations, changes in community structure and the DMSPp parameters were largely driven by increasing temperature. The observed changes were also consistent with the phytoplankton-DMS-albedo climate feedback mechanism proposed in the Charlson-Lovelock-Andreae-Warren (CLAW) hypothesis.


PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0239895 ◽  
Author(s):  
Alan M. Friedlander ◽  
Whitney Goodell ◽  
Pelayo Salinas-de-León ◽  
Enric Ballesteros ◽  
Eric Berkenpas ◽  
...  

Check List ◽  
2013 ◽  
Vol 9 (3) ◽  
pp. 533 ◽  
Author(s):  
Ascensão Ravara ◽  
Maria Helena Moreira

The present study provides a checklist of the polychaete fauna collected on the continental shelf off Aveiro (NW Portugal), within an area located between latitudes 40°30’N and 40°50’N and longitudes 8°40’W and 9°20’W, and a depth range of 8 to 185 m. The list includes 136 species, belonging to 37 families, from which 19 are new records for the Portuguese coast (Isolda pulchella, Mesochaetopterus sagittarius, Aphelochaeta multibranchis, Chaetozone cf. vivipara, Diplocirrus hirsutus, Goniadella gracilis, Gyptis mediterranea, Lumbrinerides crassicephala, Eumida bahusiensis, Eumida ockelmanni, Nereiphylla paretti, Phyllodoce rosea, Glyphohesione klatti, Malmgreniella arenicolae, Prionospio aluta, Pseudopolydora paucibranchisata, Pseudopolydora pulchra, Scolelepis mesnili, Polycirrus cf. medusa). The shelf off Aveiro presents a well- defined pattern of sediment distribution, with finer sand on the inner (8–22 m depth) and the outer (94–184 m depth) parts of the shelf and coarser sediments on the mid-shelf. The distribution of polychaete assemblages follows closely the aforementioned sedimentary pattern, showing different specific composition and structure in each of the three areas. Depth was also found to play an important role in the distribution of some polychaete species.


2001 ◽  
Vol 52 (4) ◽  
pp. 513 ◽  
Author(s):  
Alan Williams ◽  
Nicholas J. Bax

A multi-scale, multi-gear survey identified the spatial structure and compositions of fish communities from a range of seabed types on the south-eastern Australian continental shelf (25 m to ~200 m depth). Most communities are species-rich and contain many shared species. Multivariate analysis of distributions of 201 fishes showed communities to be correlated with depth, latitude and seabed type;correlation with hydrodynamic climate is suggested by patterns in morphology. Depth-related patterns occurred on soft-sediment and hard substrata; strong latitudinal (south-west/north-east)patterns identify the area as a faunal transition zone with a major faunal disjunction extending across the shelf. Community patterns were overlaid on distributions of substrata to produce a biophysical map. This mapping process is discussed in the context of spatial management:the ecologically significant scale at which to map habitat features and definition of management units for ecosystem-based management. A hierarchy of scaled ecological units is being developed for Australia’s National Representative System of Marine Protected Areas (NRSMPA);given the scope of the NRSMPA initiative, surrogate measures of community structure will be required. Maps of substrata and topography, interpreted in the context of the broader depth and latitudinal community structure and as modified by hydrography, may provide one useful surrogate.


2021 ◽  
pp. 101931
Author(s):  
Laura Rodrigues da Conceição ◽  
Christiane Sampaio Souza ◽  
Paulo de Oliveira Mafalda ◽  
Ralf Schwamborn ◽  
Sigrid Neumann-Leitão

2012 ◽  
Vol 100 ◽  
pp. 72-81 ◽  
Author(s):  
D. Vega Moreno ◽  
J. Pérez Marrero ◽  
J. Morales ◽  
C. Llerandi García ◽  
M.G. Villagarcía Úbeda ◽  
...  

2008 ◽  
Vol 65 (9) ◽  
pp. 1610-1619 ◽  
Author(s):  
R. J. David Wells ◽  
James H. Cowan ◽  
William F. Patterson

Abstract Wells, R. J. D., James H. Cowan Jr, and William F. Patterson III. 2008. Habitat use and the effect of shrimp trawling on fish and invertebrate communities over the northern Gulf of Mexico continental shelf. – ICES Journal of Marine Science, 65: 1610–1619. The goals of this study were to characterize habitat-specific fish and invertebrate community structure over sand, shell-rubble, and natural reef substrata, and to assess the effects of trawling on the sand and shell-rubble habitats and their associated communities during quarterly trawl surveys over a 2-year period. Fish and invertebrate communities differed significantly among habitat types [analysis of similarities (ANOSIM); Global R = 0.436, p < 0.001), and with respect to trawling exposure (ANOSIM; Global R = 0.128, p < 0.001). Habitat characteristics were quantified from video transects sampled with a remotely operated vehicle, and included percentage coverage of tubeworms, bryozoans, anemones, corals, and algae, significantly affecting fish community structure. Diversity indices differed among habitats, with the highest Shannon diversity (H′) and Pielou's evenness (J′) over shell-rubble, specifically non-trawled shell-rubble. In addition, higher values of H′ and J′ were found over trawled sand relative to non-trawled sand habitats. Length frequency distributions of several abundant fish species showed truncated size distributions over trawled and non-trawled habitats and were both habitat- and species-specific. The study describes habitat-specific differences in community structure, highlighting the differences between trawled and non-trawled areas on the northern Gulf of Mexico continental shelf.


2013 ◽  
Vol 68 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Alexandre B. Villas-Boas ◽  
Rafael Riosmena-Rodriguez ◽  
Marcia Abreu de Oliveira Figueiredo

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