Trace elements in tissues of cetacean species rarely stranded along the Israeli Mediterranean coast

In this paper we present the concentrations of Hg, Cd, Se, Pb, Cu, Mn, Zn and Fe in organs of 6 non-common specimens of cetaceans that were stranded along the Israeli Mediterranean coast (IMC), during 2002–2010: two fin whales, one minke whale, one Cuvier’s beaked whale, one rough-toothed dolphin, and one Risso’s dolphin. Most of the specimens were calves stranded by accident. Concentrations of Hg and Cd were low in tissues of the baleen whales and higher in the toothed whales, with maximum concentrations of 1067 mg kg⁻¹ Hg in the liver of the Risso’s dolphin and 29 mg kg⁻¹ Cd in the kidney of the Cuvier’s beaked whale. As far as we are aware, this is the first report of trace elements in baleen whales in the Eastern Mediterranean, and the first report of trace elements in minke whale and rough-toothed dolphin in the Mediterranean.     

An adjustment of benthic ecological quality assessment to effects of salinity

In the last decade a politically inspired marine protection movement arose in the European Union. This movement leads to an holistic strategy. Merging the Water Framework Directive (WFD) and the Marine Strategy Directive (MSD) along the European coastline demands sophisticated ecological classification procedures. The ‘Benthic Quality Index’ (BQI) is one of several indices created in view of the WFD. We used the dynamic species reference system ES_500.05 to test the capability of BQI to exclude primary environmental factors including the salinity gradient and depth (a proxy for the oxygen regime) from the ecological quality (EcoQ) assessment.A macrozoobenthos dataset of the southern Baltic Sea spreading over more than 20 years and over 100,000 km² was used for the EcoQ assessment. Quality assurance rules were applied to the record set and an analytical dataset of 936 sampling events with 20,451 abundance records was used in the analysis. We show that the natural salinity gradient has a severe impact on the BQI based EcoQ. We adapted the calculation procedure to reduce the salinity effects to a minimum.According to the adaptation 503 sensitivity/tolerance values for 87 species were computed. These values were calculated within seven salinity ranges from 0 to >30 PSU and two depth zones. These values can be used as a reference for further investigation in the Baltic and other areas with similar environmental conditions.     

Phytoplankton abundance, biomass and diversity within and between Pantanal wetland habitats

During the high water season, the flooding reduces environmental heterogeneity in aquatic ecosystems of the Pantanal wetland. When the water level recedes, lakes and channels are formed as individual systems. Therefore, we expected the spatial heterogeneity during the low water phase resulting in changes on biological communities leading to high phytoplankton abundance, biomass and diversity within and between habitats. To test this hypothesis, we analyzed eight freshwater systems (five oxbow lakes, two channels, and the river) during the low water period. Phytoplankton biomass, abundance, diversity (alpha, beta, gamma) and diversity metrics as richness (species per sample), Shannon diversity (H′) and evenness were measured in all systems along with nutrient concentrations, zooplankton and bacteria abundances. We found 97 species as gamma diversity. The alpha diversity was unexpectedly low in comparison to most other South American floodplain systems (38 species in river, 24 in channels and 29 in lakes). Also, the systems are relatively similar in composition (beta diversity, 28%). Connectivity differences between systems highlighted differences in phytoplankton abundance and biomass (fresh weight) ranging from 1428 ind mL⁻¹ (river) to 3710 ind mL⁻¹ (lakes) and from 0.71 mg L⁻¹ (river) to 2.9 mg L⁻¹ (lakes), respectively. However, our results did not indicate significant differences in phytoplankton species richness between the systems during the low water. Our main conclusions are that local factors may be responsible for changes on phytoplankton community and the time of isolation during the low water phase was not sufficient to promote changes in phytoplankton diversity between the habitats.     

Quantifying the suspended sediment discharge to the ocean from the Markham River,Papua New Guinea

The Markham River is a small river draining a tropical mountain range with altitudes between 1000 and 3000 m and discharges directly into a submarine canyon, the head of which is at 30 m depth and reaches depths of 500 m only 4 km from the shore. As such, the Markham discharge system serves as a possible analogue for rivers discharging onto margins during low stands of sea-level. Located in a tectonically active area and with high rainfall, sediment supply is high and episodic and is sometimes related to catastrophic mountain landslides. The river has an estimated sediment load of 12 Mt yr⁻¹. Occasionally, high energy flows are generated at the river mouth which is evident from the channel morphology and sediment distribution. Profiles of salinity and suspended sediment concentrations (SSC) show that sediment is dispersed via a plume with components at both the surface, intermediate depth along isopycnal surfaces and near the sea bed. The dispersal pattern of the surface freshwater plume is largely determined by the buoyancy force. The surface plume is very thin with salinity gradients 15 ppt m⁻¹ while a Richardson number greater than unity suggested that the mixing zone is highly stratified. Estimates of the horizontal sediment flux gradient of the surface plume along the estuary axis suggest that about 80% of the sediment discharged is lost from the plume within a distance of 2 km from the river mouth. Particle fall velocities estimated from the vertical flux indicate values less than those of flocculated material. Layers of sediment with SSCs between 500 and 1000 mg l⁻¹ were observed at intermediate depths and near the seabed during periods of both high and intermediate discharge. The mass of sediment in a SSC layer at intermediate depths between 150 and 250 m within the canyon channel was estimated to be equivalent to an average of 2 to 3 days of Markham sediment discharge. SSCs near the seabed of between 250 and 750 mg l⁻¹ suggest that layers of significantly elevated density exist near the seabed, moving under the influence of gravity down steep seabed slopes of the Markham canyon.     

The behaviors and sources of dissolved arsenic and antimony in Bohai Bay

In this paper, we determined the concentrations of antimony species (antimonite (Sb(III)), antimonate (Sb(V)) and dissolved inorganic antimony (DISb)) and arsenic, in Bohai Bay seawaters, as well as the relationships of the analytes with environmental factors such as seawater characteristics (e.g., suspended particulate material (SPM), salinity and total organic carbon (TOC)), heavy metals, nutrients and phytoplankton species, and evaluated the sources of arsenic and antimony. Dissolved arsenic and antimony concentrations in the surface waters were ranging spatially from 1.03 to 1.26 ng/ml and 0.386 to 1.075 ng/ml, with mean values of 1.18 and 0.562 ng/ml, respectively. Sb(V) as the prominent chemical species constituted about 89%. Regarding arsenic concentrations in the surface waters, there was a tendency for a small variation. However, antimony species concentrations were much variable than arsenic. The highest arsenic and antimony concentrations were found near the Haihe Estuary. These distribution patterns were controlled mainly by environmental factors, biological activities and sources. In this region, DISb and Sb(V) negatively correlated with salinity. Besides, arsenic and antimony correlated well with the nutrients, chlorophyll a and phytoplankton, implying that arsenic and antimony had been involved in biological cycling. In addition, according to our estimate, about 333.5×10⁸ mg/year of arsenic and 454.2×10⁸ mg/year of antimony reached Bohai Bay via rivers.     

Suspended sediment fluxes at an intertidal flat: The shifting influence of wave,wind, tidal,and freshwater forcing

Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment fluxes are dominated by increases in tidally averaged SSC and flow. Runoff and wind-induced circulation contribute to an order of magnitude increase in tidally averaged offshore flow, while waves and seiching motions from wind forcing cause an order of magnitude increase in tidally averaged SSC. Sediment fluxes during calm periods are dominated by asymmetries in SSC over a tidal cycle. Freshwater forcing produces sharp salinity fronts which trap sediment and sweep by the sensors over short (∼30 min) time scales, and occur primarily during the flood. The resulting flood dominance in SSC is magnified or reversed by variations in wind forcing between the flood and ebb. Long-term records show that more than half of wind events (sustained speeds of greater than 5 m/s) occur for 3 h or less, suggesting that asymmetric wind forcing over a tidal cycle commonly occurs. Seiching associated with wind and its variation produces onshore sediment transport. Overall, the changing hydrodynamic and meteorological forcing influence sediment flux at both short (minutes) and long (days) time scales.     

Climate warming and the onset of salinization: Rapid changes in the limnology of two northern plains lakes

Water resources of the interior plains region of North America may be adversely affected by climate warming. The climate records of the Battleford region (west central Saskatchewan) indicate that mean annual temperatures have risen by 0.71 °C and mean annual minimum temperatures have risen by 1.03 °C from 1894 to 2007. Snowfall has also increased but total precipitation has not. Concomitant with periodic declines in precipitation, lake elevation has declined and salinity has increased in Jackfish and Murray lakes from 1938 to 2004. This long term increase in salinity is predicted to have caused an approximate 30% loss in diversity of macrobenthos. Phosphorus concentrations have also increased significantly, and Jackfish and Murray lakes would be classified as eutrophic by freshwater trophic indices. However, despite large increases in nutrients in both lakes, algal biomass has not increased and water transparency has not decreased. Although the total amount of planktonic biomass in Jackfish and Murray’s food web is similar to that of freshwater lakes, these lakes contain very low algal biomass (measured as chlorophyll a). In fact, such low algal biomass has not been previously observed in such dilute systems. The algal community in these shallow Prairie lakes appears to be very sensitive to slight changes in climate, and future climate driven increases in salinity of prairie lakes may result in large reductions in algal primary productivity.     

Melting of enstatite from 13 to 18 GPa under hydrous conditions

Experiments on MgSiO₃ enstatite were conducted in the pressure range from 13 to 18 GPa under hydrous conditions in order to clarify the effect of water on the melting phase relations of enstatite at pressures corresponding to the Earth’s mantle transition zone. In some previous experiments [Geol. Soc. Am. Bull. 79 (1968) 1685; Phys. Earth Planet. Inter. 85 (1994) 237], incongruent melting behavior to form Mg₂SiO₄ forsterite and SiO₂ enriched liquid up to 5 GPa was observed, and congruent melting behavior at pressures up to 12 GPa was observed. Under hydrous conditions, we found that the melting reaction changes from congruent to incongruent at around 13.5 GPa. Liquid formed above 13.5 GPa is enriched in MgO component relative to MgSiO₃ because it coexists with stishovite (SiO₂). Moreover, the solidus temperature decreases drastically at around 13.5 GPa, in unison with the change in the melting reaction. The solidus temperature is about 1400 °C at 13 GPa, but approximately 900 °C at 15 GPa. Our results show that the liquidus phase changes from clinoenstatite to stishovite with increasing pressure and water content above 13.5 GPa. MgSiO₃ enstatite is one of the major constituent minerals in the Earth’s mantle, and it is expected that MgO-enriched liquid will be generated in the transition zone if water is present.     

Impact of multispecies diatom bloom on plankton community structure in Sundarban mangrove wetland,India

A multispecies bloom caused by the centric diatoms, viz. Coscinodiscus radiatus, Chaetoceros lorenzianus and the pennate diatom Thalassiothrix frauenfeldii was investigated in the context of its impact on phytoplankton and microzooplankton (the loricate ciliate tintinnids) in the coastal regions of Sagar Island, the western part of Sundarban mangrove wetland, India. Both number (15–18 species) and cell densities (12.3 × 10³ cells l⁻¹ to 11.4 × 10⁵ cells l⁻¹) of phytoplankton species increased during peak bloom phase, exhibiting moderately high species diversity (H′ = 2.86), richness (R′ = 6.38) and evenness (E′ = 0.80). The diatom bloom, which existed for a week, had a negative impact on the tintinnid community in terms of drastic changes in species diversity index (1.09–0.004) and population density (582.5 × 10³ to 50 × 10³ ind m⁻³). The bloom is suggested to have been driven by the aquaculture activities and river effluents resulting high nutrient concentrations in this region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. MODIS-Aqua derived chlorophyll maps have been interpreted.     

On the history of chloride concentrations in the River Lippe (Germany) and the impact on the macroinvertebrates

The River Lippe is situated at the northern part of the rhenish-westphalian coal mining area, Germany and has a long history of being affected by mining water discharge. There has, however, been a massive decrease in the discharge of mining water over the past few decades. While early in the last century concentrations of up to 3500 mg l⁻¹ of chloride were observed, the mean concentration is now below 400 mg l⁻¹. At the same time the water quality has improved greatly so factors other than chloride concentration may be influencing the macroinvertebrate community.Macroinvertebrate data collected from three sites along the River Lippe was analyzed for a change in the occurrence of salt tolerant species in an area where mining water discharge ended in 2000. It was found that also during the period of discharges the macroinvertebrate community was dominated by freshwater species and therefore the impact of mining water discharges in the upper River Lippe is considered to be minor.It was also found that for some species (Nais elinguis, Bithynia tentaculata and Gammarus tigrinus) their proposed salinity preference did not correlate with their occurrence in the field. This may be an area that requires further research.     

Effect of salinity on acute copper and zinc toxicity to Tigriopus japonicus: The difference between metal ions and nanoparticles

We investigated the effects of salinity (5‰, 15‰, 25‰ and 35‰) on metal ion (Cu and Zn) and nanoparticle (NP) CuO and ZnO toxicity to Tigriopus japonicus. Increasing the test media volume without renewal increased the 96-h LC₅₀ for Cu (32.75 mg L⁻¹) compared to the reported value (3.9 mg L⁻¹). There was no significant difference in acute toxicity at different salinities between acclimated and unacclimated T. japonicus (p > 0.05). Increasing salinity decreased the dissolved concentrations of Cu and Zn ions due to the precipitation of the metal ions, consequently reducing the acute toxicity to T. japonicus. The effect of salinity on acute CuO and ZnO NP toxicity was similar to that on metal ion toxicity. Since the aggregation of NPs generally enhanced at higher salinities, both the dissolution and aggregation of CuO and ZnO NPs may control the effect of salinity on acute toxicity to T. japonicus.     

Oceanography of coastal and riverine waters around Timika, West Central Irian Jaya, Arafura Sea

Oceanographic studies have been carried out in coastal and riverine waters of the area around Timika, West Papua in November 1999, March–April, July and November 2000. The temperature of the seawater along the coast is around 28 °C in winter (November 99), rising to 30.0 °C (November 00). In the open sea, 30 miles off the coast at 40 m water depth, the temperature is >30 °C with no stratification. Water temperature near the coast is consistently lower than in the open sea. This is thought to be due the cooling effect of the land, being densely covered by mangrove forest. In the upper parts of the Kamora, West Tipuka, East Tipuka, Ajkwa, Minajerwi, Mawati and Otakwa Rivers, at salinity zero psu, water temperature varies between 24.6 and 26.2 °C, which is as cold as the temperature in the upwelling Banda Sea to the NW. Some of these rivers are fed by glacial melt water from the high mountains to the east. At mid estuary, warm seawater is found under the cooler river water.Salinity near this coast varied between 24 and 30, and offshore salinity was 31–33 with no stratification. Inshore surface waters were turbid (11–14 ntu), and near bottom waters were generally much more turbid from river sediment supply and tidal resuspension. The Ajkwa River estuary has the highest turbidity (750 ntu) at zero salinity. Offshore waters were very clear (5.0–6.0 ntu), and there was no increase in turbidity near the bottom.     

The dilution and dispersion of ballast water discharged into Goderich Harbor

Observations are presented on dilution and dispersion rates of ballast water discharged under normal operational conditions at the semi-enclosed port of Goderich, Ontario. The ballast water was tagged with Rhodamine-WT dye and microscopic magnetically-attractive tracer particles. Maximum concentrations of dye immediately after discharge were diluted to 1-5% of initial ballast tank concentrations, and within 3 days had decreased to less than 0.1% of initial concentrations. Inside the harbor, there was 10-20% of the ballast water still present after 2 days, consistent with a flushing rate of 0.8-1.15 day⁻¹. Magnetic particles were collected up to 7.5 km outside the harbor after one day, consistent with a dilution factor of order 10⁵ outside the harbor. The results of this study are discussed in the context of ballast water discharge standards proposed by the International Maritime Organization to minimize the introduction of aquatic nonindigenous species through ships’ ballast water and sediments.     

Spatial and temporal variability of seawater properties,current velocity and SPM concentration off Cassino Beach-Rio Grande-Southern Brazil

Water column profiles and near-bed time series of pressure, current velocity, suspended-particulate matter (SPM) concentration and seawater temperature and salinity were collected during three short cruises carried out in May 2005 in the shoreface and inner shelf area adjacent to Cassino Beach, southern Brazil. The measurements were part of the Cassino Experiment, a project conducted at an open, sandy coastal area known for the occurrence of patches of fairly large amounts of muddy sediments that are sporadically fluidized, transported onshore and eventually stranded on the beach. The study area is close to the Patos Lagoon mouth, being influenced by its water and suspended-sediment discharge. The presence of the Patos Lagoon outflow on the inner shelf was detected in one of the cruises (May 13) through measurements of near-surface salinity: while close to shore salinity was 29.4, a minimum value of 13.8 was measured at ∼10 km from the coast. Four days later, no trace of the plume was detected in the area. Regarding seawater temperature, no large temporal or spatial variability was documented with measured values ranging from 19.3 to 20 °C. Water column currents were prominently to N and NE, except at the outermost station, located ∼42 km from the coast, where NW-directed flows were observed at surface and mid-depth. Maximum near-bed current velocity oscillated between 18 and 42 cm s⁻¹ in the east–west direction and between 14 and 42 cm s⁻¹ in the north–south direction. Near-surface concentration of SPM oscillated between 11 and 99 mg L⁻¹, in general one order of magnitude lower than near-bed values. However, near-bed concentration of SPM showed large spatial variability: the highest value (2200 mg L⁻¹) was yielded by a water sample collected at ∼8 m water depth, at a station located ∼2 km away from the shoreline; two water samples collected 500 m, apart from this station, yielded SPM concentrations of 148 and 205 mg L⁻¹, one order of magnitude lower. Spectral analyses of near-bed current speed and SPM concentration indicate the relevance of oscillations in the low-frequency (<0.05 Hz) range. Detailed sampling of bottom sediment indicated that in May 2005 the mud patch was centered at ∼8.5 m water depth.     

Biological effects of anthropogenic salt-load on the aquatic Fauna: A synthesis of 17 years of biological survey on the rivers Werra and Weser

The reduction and the smoothened amplitudes of the chloride concentrations since 2000 have resulted in a gradual positive development of the aquatic fauna in the River Werra. In the salinized section of the river increasing species numbers have been determined along the salinity gradient, which shows maximum chloride concentrations of about 2500 mg/l, maximum potash concentrations at approximately 200 mg/l, and magnesia concentrations peaked at 320 mg/l. As an immediate consequence of the reduction in salt concentration the immigration of various caddis fly species into the lower River Werra was observed. The Number of taxa per sample rose from 5 to more than 30 in the lower Werra region. Changes in species-richness could be seen more frequently in river sections where chloride concentrations fluctuated around 1500 mg/l.     

First record of Prorocentrum lima (Dinophyceae) inside harbor areas and along the Abruzzo region coast, W Adriatic

Prorocentrum lima (Ehrenberg) Dodge has been found for the first time during the summer of 2007 inside Ortona harbor and along the coast of the Abruzzo region, a slightly eutrophic area influenced by runoff from a nearby river. The investigations were conducted in two harbors and at six coastal sampling stations. Samplings were conducted using a phytoplankton net and with a pump. Average P. lima cellular concentrations were 3.2 × 10⁴ cells L⁻¹. Other well-known toxic and potentially toxic phytoplankton species have been considered. The number of toxic cells from net samples were higher than the numbers of toxic cell samples collected without the net. Occurrences of P. lima with abiotic factors revealed that temperature was positively correlated with P. lima abundance (p = 0.01), while salinity was highly negatively correlated with P. lima presence (p = 0.001). The total phytoplankton community was studied.     

Wind-driven diversion of summer river runoff preconditions the Laptev Sea coastal polynya hydrography: Evidence from summer-to-winter hydrographic records of 2007–2009

This paper examines the role of atmospheric forcing in modifying the pathways of riverine water on the Laptev Sea shelf, using summer-to-winter hydrographic surveys from 2007 to 2009. Over the two consecutive winter seasons of 2007–2008 and 2008–2009 in the area of the winter coastal polynya, our data clearly link winter surface salinity fields to the previous summer conditions, with substantially different winter salinity patterns preconditioned by summer atmospheric forcing. In the summer of 2007, dominant along-shore westerly winds in the cyclonic regime force the Lena River runoff to flow eastward. In contrast, in the summer of 2008, dominant along-shore easterly winds over the East Siberian Sea and on-shore northerly winds over the Laptev Sea in the anticyclonic regime lock the riverine water in the vicinity of the Lena Delta. Over the coastal polynya area in the southeastern Laptev Sea these patterns precondition a surface salinity difference of 8–16 psu between the winters of 2008 and 2009. Overall, this indicates a residence time of at least half a year for riverine water on the Laptev Sea shelf. Future climate change associated with an enhanced summer cyclonicity over the eastern Arctic may turn more riverine water eastward along the eastern Siberian coast, resulting in weaker vertical density stratification over the Laptev Sea shelf, with possible impact on the efficiency of vertical mixing and polynya dense water production.     

PCBs and organochlorine pesticides in Hector’s (Cephalorhynchus hectori hectori) and Maui’s (Cephalorhynchus hectori maui) dolphins

Polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels were determined in blubber samples collected from stranded and incidentally by-caught Hector’s (Cephalorhynchus hectori hectori) and Maui’s (Cephalorhynchus hectori maui) dolphins from New Zealand waters between 1997 and 2009. PCBs (45 congeners) and a range of OC pesticides including dieldrin, hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), along with its metabolites DDE and DDD were determined. OC pesticides dieldrin, p,p′-DDE, p,p′-DDD and p,p′-DDT were present at the highest concentrations. Sum DDT concentrations ranged from 93.7 to 8210 (Mean = 1358, S.D = 1974) and 252.4 to 57,390 (Mean = 12,389, S.D = 18,161) μg/kg wet weight in females and males, respectively. Similarly, Σ45CB concentrations ranged from 45.5 to 981.3 (Mean = 333.2, S.D = 265.8) and 60.5 to 5574 (Mean = 1833, S.D = 1659) μg/kg wet weight in females and males, respectively. The transfer of ΣDDTs and summed PCBs (both as ΣICES7CBs and Σ45CBs) between a pregnant female and her unborn fetus was calculated at 5.7% and 4.3%, respectively. As the fetus was close to term, this likely represents the degree of placental transfer. Concentrations of OC pesticides determined in the present study are higher than those previously reported for Hector’s dolphins. Sum DDT and DDE/ΣDDT levels calculated reveal New Zealand’s legacy of DDT usage, particularly off the east coast of the South Island.     

The effect of CO2 acidified sea water and reduced salinity on aspects of the embryonic development of the amphipod Echinogammarus marinus (Leach)

We investigated the effect of CO₂ acidified sea water (S = 35, 22 and 10_PSU) on embryonic development of the intertidal amphipod Echinogammarus marinus (Leach). Low pH, but not low salinity (22_PSU), resulted in a more protracted embryonic development in situ although the effect was only evident at low salinity. However reduced salinity, not pH, exerted a strong significant effect, on numbers and calcium content of hatchlings. Females exposed to low salinity (10_PSU) did not carry eggs through to hatching. There was no significant difference in the number of viable hatchlings between females cultured in 22 and 35_PSU but the exoskeleton of the juveniles at 22_PSU contained significantly less calcium. Ocean acidification may affect aspects of E. marinus development but exposure to realistic low salinities appear, in the short term, to be more important in impacting development than exposure to CO₂ acidified sea water at levels predicted for 300 years time.     

Controls on shell Mg/Ca and Sr/Ca in cultured planktonic foraminiferan, Globigerinoides ruber (white)

Mg/Ca and Sr/Ca ratios were determined on a single species of planktonic foraminiferan, Globigerinoides ruber (white), collected from the Gulf of Eilat and cultured in seawater at five different salinities (32 to 44), five temperatures (18 to 30 °C) and four pH values (7.9 to 8.4). The Mg/Ca-temperature calibration of cultured G. ruber (with an exponential slope of 8 ± 3%/°C) agrees well with previously published calibrations from core-tops and sediment traps. However, the dependence of Mg/Ca on salinity (with an exponential slope of 5 ± 3%/psu) is also significant and should be included in the calibration equation. With this purpose, we calculated a calibration equation for G. ruber dependent on both temperature and salinity within the 95% confidence limits:

Mg/Ca(mmol/mol)=exp[0.06(±0.02)*S(psu)+0.08(±0.02)*T(°C)−2.8(±1.0)],R²=0.95