22 research outputs found
The response of nematodes to deep-sea CO2 sequestration : a quantile regression approach
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 57 (2010): 696-707, doi:10.1016/j.dsr.2010.03.003.One proposed approach to ameliorate the effects of global warming is sequestration of
the greenhouse gas CO2 in the deep sea. To evaluate the environmental impact of this
approach, we exposed the sediment-dwelling fauna at the mouth of the Monterey
Submarine Canyon (3262 m) and a site on the nearby continental rise (3607 m) to CO2-
rich water. We measured meiobenthic nematode population and community metrics
after ~30-day exposures along a distance gradient from the CO2 source and with
sediment depth to infer the patterns of mortality. We also compared the nematode
response with that of harpacticoid copepods. Nematode abundance, average sediment
depth, tail-group composition, and length: width ratio did not vary with distance from
the CO2 source. However, quantile regression showed that nematode length and
diameter increased in close proximity to the CO2 source in both experiments. Further,
the effects of CO2 exposure and sediment depth (nematodes became more slender at
one site, but larger at the other, with increasing depth in the sediment) varied with body
size. For example, the response of the longest nematodes differed from those of
average length. We propose that nematode body length and diameter increases were
induced by lethal exposure to CO2-rich water and that nematodes experienced a high
rate of mortality in both experiments. In contrast, copepods experienced high mortality
rates in only one experiment suggesting that CO2 sequestration effects are taxon
specific.The Department of Energy
Office of Biological and Environmental Research supported this research under award
numbers DEâFG02â05ER64070 and DEâFG03â01ER63065 and the U.S. Department of
Energy, Fossil Energy Group (award DEâFC26â00NT40929). We also appreciate
significant support provided by the Monterey Bay Aquarium Research Institute (project
200002)
Modern approaches to marine antifouling coatings
Marine structures such as platforms, jetties and ship hulls are subject to diverse and severe biofouling. Methods for inhibiting both organic and inorganic growth on wetted substrates are varied but most antifouling systems take the form of protective coatings. Biofouling can negatively affect the hydrodynamics of a hull by increasing the required propulsive power and the fuel consumption. This paper reviews the development of antifouling coatings for the prevention of marine biological fouling. As a result of the 2001 International Maritime Organization (IMO) ban on tributyltin (TBT), replacement antifouling coatings have to be environmentally acceptable as well as maintain a long life. Tin-free self-polishing copolymer (SPC) and foul release technologies are current applications but many alternatives have been suggested. Modern approaches to environmentally effective antifouling systems and their performance are highlighted
Perylene toxicity in the estuarine environment of Ria de Aveiro (Portugal)
Perylene, a 5-ring polycyclic aromatic hydrocarbon is common in estuarine sediments and its toxicity in the benthic and planktonic compartments is not yet clarified. The objectives of this work were: (1) to follow the toxicity of high concentrations of perylene (110 mg lâ1) on benthic bacteria and macrofauna (amphipod Corophium multisetosum); (2) to determine the effects of a low load of perylene (2 ÎŒg lâ1) on the metabolism of suspended bacteriobenthos after 9-day exposure, mimicking the effects of tidal erosion; (3) to contrast the effects of this low perylene load on the particle-free bacterioplankton and on the suspended and particle-adhered bacteriobenthos. No impact was detected in bacterial abundance exposed to 110 mg perylene lâ1 for 9 days. This concentration of perylene evoked no acute effects in C. multisetosum but, chronic toxicity assays revealed statistically significant negative effects on survival, growth and number of pregnant females. The bacterioplankton and the suspended bacteriobenthos, exposed to 2 ÎŒg perylene lâ1 during 2 weeks, responded with altered profiles of activity when compared to the control suspension. These values ranged, respectively, for bacterial biomass production from 134 to 210 and from 24 to 184 ÎŒg C lâ1 hâ1, for aminopeptidase from 1824 to 11,127 and from 1464 to 15,488 nmol lâ1 hâ1, and for ÎČ-glucosidase from 87 to 400 and from 57 to 1278 nmol lâ1 hâ1. The rate of oxygen consumption in the perylene-exposed suspension (0.04â2.85 mmol O2 kgâ1 dw sed hâ1) exhibited a clearly distinct profile in relation to the control (0.57â1.60 mmol O2 kgâ1 dw sed hâ1). The overall reactivity of the bacteriobenthos to perylene was interpreted as the result of toxic pressure followed by evolution of a diverse bacterial community