37 research outputs found
Energy balance of the clam Ruditapes decussatus (Linnaeus, 1758)
The effect of food ingestion and clam size on absorption efficiency, absorption rate and oxygen consumption of the clam Ruditapes decussatus (L., 1758) was studied. Absorption efficiency (AE) was related to the ingestion rate (IR) following the non-lineal equation AE = 0.836 + e-0.64/IR (P 0.01; n = 26; r² = 0.321) No significant relationship as found between AE and clam live weight, whereas there was a relationship between absorption rate (AR) and IR, following the expression AR = 0.8248 IR - 0.0344 (P 0.001; n = 26; r² = 0.964) The maintenance food ration for a 2 g (live weight) clam was estimated as 1.528 J/h, equivalent to a daily food ration of 0.08 mg organic matter/g clam live weight.Se estudia el efecto de la ingestión de alimento y el tamaño de las almejas sobre la eficiencia de absorción, la tasa de absorción y el consumo de oxígeno de Ruditapes decussatus (L., 1758). La eficiencia de absorción (EA) se relaciona con la tasa de ingestión (TI) siguiendo el modelo no lineal EA = 0,836 + e-0,64/TI (P 0,01; n = 26; r² = 0,321) Entre EA y el peso vivo de las almejas no existe una relación significativa, mientras que sí la hay entre la tasa de absorción (TA) y TI, y responde a la ecuación TA = 0,8248 TI - 0,0344 (P 0,001; n = 26; r² = 0,964) La ración de mantenimiento de una almeja de 2 g de peso vivo es de 1,528 J/h, que se corresponde con una dieta diaria de 0,08 mg de materia orgánica por gramo de peso vivo.Instituto Español de Oceanografí
Seasonal variability of antioxidant biomarkers in mussels Mytilus galloprovincialis from the Spanish N-NW coast.
Marine organisms are highly seasonal
animals in relation to their physiology which depends, among other
factors, on their annual cycle of reproduction. In bivalves, reproductive
cycle is regulated by two main environmental factors: temperature and
food availability. Specifically, bivalves are undergoing high variable
environmental conditions. Integrated pollution monitoring carried out by
the IEO along the N-NW coast of Spain has evidenced that the
variability of the environmental conditions produce spatial differences in
mussel condition which seems to mask the biomarker responses to
pollution. Thus, there is a need to study the natural variability of
biological responses used as pollution biomarkers at different seasons
and in different habitats in order to establish an adequate link between
chemical pollution and biological responses. This study aims to assess
the natural variability of some biomarker responses on the mussel
Mytilus galloprovincialis in 5 different sites from the Spanish Marine
Pollution Monitoring Program which are differentiated in their natural
ecology and their anthropogenic pressure. The potential influence of
environmental and endogenous factors that can cause biomarker´s
seasonal fluctuations was examined. Biomarkers analyzed in this study
are considered among the most usefull biological tools applied in
pollution monitoring programs, including exposure indicators
(superoxide dismutase –SOD-, catalase –CAT-, glutathione reductase –GR-,
glutathione peroxidase –GPx-, glutathione-s-transfersase –GST-) and a
damage indicator (lipid peroxidation –LPO-). Mussel biological
characterization from a histological and anatomical point of view was
also performed. Results evidenced that biomarkers were clearly
influenced by the annual cycle (all of them were affected by the season)
but also significant differences between sites were found in some
biomarkers (GR and GST). Thus, not only environmental but also
endogenous factors must be considered in monitoring programs in the
study of biomarkers responses.Society of Environmenta Toxicology and Chemistry (SETAC
Impact assessment of agricultural inputs into a Mediterranean coastal lagoon (Mar Menor, SE)
The Mar Menor is a coastal lagoon threatened by the development of intensive agriculture in
the surrounding areas. Large amounts of pesticides from these areas are discharged into El Albujón, a
permanent watercourse flowing into the lagoon.
We have used a multi-biomarker approach to assess the biological effects arising in bivalve species
affected by agricultural pollution. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AchE),
oxidative stress (catalase, CAT; glutathione reductase, GR and lipid peroxidation, LPO), phase II
biotransformation of xenobiotics (glutathione S-transferase, GST) and physiological stress (scope for
growth, SFG) were measured in clams transplanted to four sites of the lagoon (two reference sites and
two sites affected by the dispersion of the effluent of the El Albujón), for exposure periods of 7 and 22
days.
The hazards of this effluent were also examined by simultaneously measuring up to 83 contaminants
(pesticides, PCBs, PAHs and others) in samples of fresh water from the watercourse mouth and
seawater from the deployed sites, as well as the bioaccumulation of organochlorinated compounds and
PAHs in the transplanted animals.
Biomarker responses showed marked differences between reference and affected sites after 7 and 22
days. However it was only after 22 days that Principal Component Analysis (PCA) of the biomarker
responses distinguished between clams deployed in sites affected by the dispersion of the effluent of
the watercourse and those from the reference sites. The chemical analysis of water showed high
concentrations of pesticides close to El Albujón watercourse mouth, with the greatest input flux
corresponding to the organophosphate chlorpyrifos, followed by pendimethalin and naphthalene, and
at lower levels acenaphthene, terbuthylazine-desethyl and chlorpyrifos-methyl. In this regard, PCA
analysis showed that the biological effects of the mixture of pesticides in caged clams after 22 days
were reduced levels of AchE and SFG and increased levels of GR and phase II GST activity. An
Integrated Biomarker Response index was calculated from the combination of these biomarkers,
proving useful for the assessment of the impact of agricultural pollution in caged clams.Preprint3,761