Beneficial use of dredged sediments, either in harbours or waterways, is based on their potential as alternative resources. Such sediments can be considered as bulk materials for industrial needs, which is predicated on their current waste status or meeting end-of-waste constraints. They also can be an integral part of beneficial use projects using sediments as a bulk component, including civil engineering and landscaping. This is particularly important for beneficial use projects focusing on climate change effects mitigation, such as flood protection works, coastline defence or littoral urban areas redevelopment. When dredged sediment is used as a bulk material, its acceptability is based on an assumed homogeneity of its properties. On-site analyses allow pre-dredging detailed mapping at a denser scale than laboratory ones; monitoring dredgings during operations and during processing; and continuous control of their properties at the implementation site. This is currently possible only for a selection of inorganic analytes. When dredgings are part of a larger beneficial use project, on-site analyses facilitate first the baseline survey and the sediment source characterisation. Continuous monitoring of the sediment load allows a fast detection of contamination hot spots and their adequate management. Site survey via on-site instruments allow end users and communities to check themselves the contamination level, hence acceptability is better. On-site dredged sediment analyses monitor both building properties and environmental compliance; soil and sediment analyses at receiving sites; surface and groundwater, either for impact assessment or for monitoring works. On-site instruments provide immediate results and allow dynamic or adaptive sampling strategies, as well as allowing operational decisions in real time. Confirmation by laboratory analyses is required for validation, but on-site sample screening for laboratory analyses improves their efficiency. The present paper was developed on the basis of an earlier presentation, which it developed and updated extensively.

Heat shock response (HSR), in terms of transcription regulation of two heat shock proteins genes hsp70 and hsp90), was analysed in a widespread tropical copepod Pseudodiaptomus annandalei. The mRNA transcripts of both genes were quantified after copepods at a salinity of 20 underwent an acclimation process involving an initial acclimation temperature of 29 degrees C, followed by gradual thermal ramping to the target exposure temperature range of 24-36 degrees C. The respective cellular HSR and organismal metabolism, measured by respiratory activity at exposure temperatures, were compared. The fold change in mRNA expression for both hsp70 and hsp90 (8-9 fold) peaks at 32 degrees C, which is very close to 32.4 degrees C, the upper thermal optimum for respiration in the species. Unexpectedly, the modelled HSR curves peak at only 3 degrees C (hsp90) and 3.5 degrees C (hsp70) above the mean water temperature (29.32 degrees C) of the copepod in the field. We propose that copepods in tropical waters adopt a preparative HSR strategy, early at the upper limit of its thermal optimum, due to the narrow thermal range of its habitat thus precluding substantial energy demand at higher temperatures. However, the model suggests that the species could survive to at least 36 degrees C with short acclimation time. Nevertheless, the significant overlap between its thermal range of lisp synthesis and the narrow temperature range of its habitat also suggests that any unprecedented rise in sea temperature would have a detrimental effect on the species.

Thermal specialization could explain the dominance of some marine crustaceans in thermostable conditions but fluctuations below their natural thermal environment should substantially disrupt physiological rates. This study shows how developmental cold acclimation below the thermal optimum significantly helps mitigate the decay of the weight-specific respiration rate (Rsp) in a widespread tropical copepod (Pseudodiaptomus annandalei Sewell, 1919) as compared to cold acclimation during the adult stage only. The measurement of routine respiration is of valuable physiological interest, as experimental results on P. annandalei identified the lower thermal limit for optimal respiration and confirmed this species as a thermal specialist given its narrow thermal window that closely overlapped the natural thermal regime in the area. The implications of a higher than expected Rsp in a colder environment during the entire life cycle as compared to traditional short-term experiments are discussed in view of the controversial theory of metabolic cold adaptation.

We investigated the effects of temperature on weight-specific respiration rates ( R sp ) of the euryhaline calanoid copepod Pseudodiaptomus annandalei collected from the Matang Mangrove Forest Reserve (Malaysia). We employed a simple experimental approach consisting of a short temperature exposure time from 24 to 36 8 C. The relationship between temperature and R sp of acclimated copepods under conditions of excess food fitted an exponential function and indicated a complete lack of acclimation at the higher temperature range. Both fine-scale temperature measurements and piecewise linear regression enabled the detection of a breakpoint produced by a significant increase in respiratory rates. It is argued that thermally stressed copepods can be detected by both a higher Q 10 above 32 8 C and monitoring this breakpoint in the metabolic response ( R sp ). Similarly, the lower Q 10 ( (cid:2) 2) indicates some degree of independence of their metabolic rates between 26 and 32 8 C, which likely corresponds to their optimal thermal window. Results are discussed in relation to body mass, feeding status and gender.

The present study investigated thermal effect and acclimation duration on oxygen consumption (R-sp) for Pseudodiaptomus annandalei, a widespread copepod in tropical and subtropical waters. The inflection point of the R:T curve at 32.4 degrees C during the developmental acclimation (DAAC) most probably indicates the upper limit of its thermal optimum for respiration. Interestingly, this upper thermal optimum for DACC closely occurred at the same temperature at which a breakpoint was previously observed during the adult acclimation (AACC). The measurement of Rsp during AACC provides a valuable tool in order to determine the upper thermal optimum for P. annandalei and most probably for many other copepods. The temporal dimension using two acclimation processes emerges as a major factor shaping the relationship between temperature and metabolic rates and would better guide how modelers should consider this essential component in order to improving climate change predictive models.

Zooplankton samples collected before (1985-86) and after (2013-14) the establishment of Kapar power station (KPS) were examined to test the hypothesis that increased sea surface temperature (SST) and other water quality changes have altered the zooplankton community structure. Elevated SST and reduced pH were detected between before and after impact pairs, with the greatest impact at the station closest to KPS. Present PAHs and heavy metal concentrations are unlikely causal factors. Water parameter changes did not affect diversity but community structure of the zooplankton. Tolerant small crustaceans, salps and larvaceans likely benefited from elevated temperature, reduced pH and shift to a more significant microbial loop exacerbated by eutrophication, while large crustaceans were more vulnerable to such changes. It is predicted that any further rise in SST will remove more large-bodied crustacean zooplankton, the preferred food for fish larvae and other meroplankton, with grave consequences to fishery production.

Biomass, abundance, gut fluorescence and electron transfer system (ETS) activity of zooplankton have been studied in the Bransfield Strait (Antarctic Peninsula). Two well-defined frontal systems were observed: (1) the so-called Peninsula front between the Transitional Bellingshausen Water (TBW) and Transitional Weddell Waters (TWW); and (2) the Bransfield front related to the Bransfield Gravity Current flowing northeastward along the slope of the South Shetland Islands. As expected, a typical pattern of plankton distribution was observed with higher phyto- and mesozooplankton in the TBW. However, our more detailed study of the Peninsula front between the TBW and TWW showed the sinking of phytoplankton and a higher abundance of large copepods on the TBW side of the front, while krill and small copepods were observed on the opposite side, in the TWW. Ageostrophic secondary circulation around the front supported a striking food web at both sides of the front. It is suggested that this pattern drives a relatively important flux of carbon, due to the sinking of phytoplankton and the production of fast sinking fecal pellets by large copepods and krill.

During the austral summer, zooplankton excretion along the western Antarctic Peninsula was studied in a contrasting hydrographic regime including coastal and oceanic waters. In coastal waters, ammonium supply by mesozooplankton indicated a low contribution to fuel primary production. In oceanic waters, however, Antarctic krill Euphausia superba contributed a significant percentage to the nitrogen requirements of primary producers. Thus, the ontogenetic migration of adult krill during austral summer should be a key factor regulating the regenerated ammonium for primary production. A significant coupling of ammonium concentration in the water column and in situ krill biomass supported the significant role of krill excretion in the epipelagic realm. Results from short-term experiments with E. superba indicated that ammonium excretion rates were much higher than previously found. Because the use of experimental metabolic rates that are close to field rates would be more appropriate, we suggest to re-assess the ammonium supplied by the epipelagic marine biota. Moreover, the outcomes of experimental krill excretion rates, in situ measurements of ammonium and a review of data on primary production suggest that Antarctic krill sustain a high proportion of the daily phytoplankton production.

Carbon dioxide production rates of mixed epipelagic copepods were measured during the so-called late winter bloom in the vicinity of the Canary Islands. Respiration rates were measured using a simple and sensitive infra-red gas analyser coupled to a manifold containing an equilibrator module to transfer seawater CO2 to the gas phase. The system allowed the determination of the carbon dioxide content of one sample in 20 to 40min. Respiration rates obtained were similar to previous oxygen consumption rates in subtropical waters. A relative wide range of carbon dioxide production rates was observed due to the metabolic condition of the organisms. Direct measurement of respiration rates after the capture showed high values (11-fold) compared to standard rates at starving conditions after only 4–6h of incubation in filtered seawater. The results showed that short-term (0.5h) CO2 production rates by copepods can be measured in relatively large incubation volumes (600ml) minimizing crowding and bottle effects. A standardized method is proposed in order to obtain comparable results of metabolic rates in marine mesozooplankton.

The measurement of mesozooplankton biomass in the ocean requires the use of analytical procedures that destroy the samples. Alternatively, the development of methods to estimate biomass from optical systems and appropriate conversion factors could be a compromise between the accuracy of analytical methods and the need to preserve the samples for further taxonomic studies. The conversion of the body area recorded by an optical counter or a camera, by converting the digitized area of an organism into individual biomass, was suggested as a suitable method to estimate total biomass. In this study, crustacean mesozooplankton from subtropical waters were analyzed, and individual dry weight and body area were compared. The obtained relationships agreed with other measurements of biomass obtained from a previous study in Antarctic waters. Gelatinous mesozooplankton from subtropical and Antarctic waters were also sampled and processed for body area and biomass. As expected, differences between crustacean and gelatinous plankton were highly significant. Transparent gelatinous organisms have a lower dry weight per unit area. Therefore, to estimate biomass from digitized images, pattern recognition discerning, at least, between crustaceans and gelatinous forms is required.

IMAGES Lehette, P. and S. Hernández-León Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria. The measurement of mesozooplankton biomass in the ocean requires the use of analytical procedures which needs the destruction of samples or, by contrast, the development of methods to estimate biomass from optical systems and appropriate conversion factors (Postel et al., 2000). The conversion of the area recorded by an optical counter or a camera has been suggested as a suitable method to estimate total biomass by converting the digitized area of an organism into individual biomass and summing up the individual biomass. In this study, crustacean mesozooplankton from subtropical waters were analyzed and direct individual dry weight of the most common groups and body area by digitized image analysis were obtained. Relationships between individual dry weight and body area agreed with other measurements of biomass obtained in a previous study in Antarctic waters (Hernández-León and Montero, 2006), suggesting a universal regression for these organisms. Gelatinous mesozooplankton from subtropical and Antarctic waters were also sampled and processed for body area and biomass. As expected, differences between these two planktonic groups (crustacean and gelatinous) were highly significant. Transparent gelatinous organisms have a lower dry weight per unit area. Therefore, to estimate biomass from digitized images, pattern recognition discerning, at least, between crustaceans and gelatinous forms are required.