Sublethal effects of contaminated sediment on Arenicola marina

Purpose

The highest concentrations of environmental contaminants are generally found in marine sediments, and there is a need for knowledge concerning how and whether they affect sediment-dwelling organisms. This study aimed to assess sublethal effects in Arenicola marina exposed to two sediments from a contaminated fjord and two reference locations with different sediment characteristics.

Materials and methods

Duplicate contaminated sediments were used to investigate the robustness of current protocols for sediment testing. The two reference sediments, with different grain sizes and total organic carbon, were collected from the outer Oslofjord and the two contaminated sediments from Frierfjord. Polychaetes were exposed in quadruplicate sediment microcosms and sampled after 1, 2, 4 and 8?weeks of exposure. Oxidative stress resistance (total oxyradical scavenging capacity, TOSC) and components comprising the energy budget (cellular energy allocation, CEA) were determined for individual polychaetes.

Results and discussion

Arenicola maintained and increased body weights over the initial 4?weeks of exposure in all groups, except in one reference sediment (Elle). There were no differences between treatments in the scavenging capacity (TOSC). The most striking difference in how polychaetes partitioned energy resources was a difference in lipid and carbohydrate allocations for Arenicola held in the contaminated sediments over the initial weeks. Cellular respiration appeared to increase in polychaetes held in the Elle sediment and decreased for polychaetes held in the two Frierfjord sediments by weeks?4 and 8. In the overall CEA, this was offset by increased energy per weight stored in the Elle group, which resulted in an overall positive CEA for polychaetes held in that sediment, whereas polychaetes in the other treatments were close to neutral. Although CEA would thus indicate that Elle polychaetes had good health status, their body weight also decreased significantly over the experimental period compared to other treatments, indicating an overall negative effect.

Conclusions

This study has shown the importance of sediment characteristics when evaluating toxicity and how resource allocation can differ dramatically over a short time span in polychaetes held in similarly contaminated sediments. There were no clear effects of sediment contamination on CEA or TOSC in the polychaete A. marina. The findings are relevant for the design of both short- and long-term sediment studies.     

The joint effect of oil and drilling agents on some invertebrate species of the Caspian Sea

The toxic effect of some chemical reagents in drilling muds has been studied for shrimp (Palaemon adspersus P.), amphipoda (Pontogammarus maeoticus S.) and mytilaster (Mytilaster lineatus G.). The toxicity has been studied for drilling agents and/or water-soluble oil fractions. The survival, growth rate, O₂ consumption and generation number of experimental organisms have been taken as toxicity criteria. Some data concerning minimum toxic, sublethal and lethal concentrations of drilling agents have been obtained. The concentration increase of water-soluble oil fractions leads to increased damage effect.     

Model Simulations of the Alkaline Dust Distribution from Estonian Sources over the Baltic Sea Basin

The model calculations of oil-shale fly ash deposition from the Narvapower plants (north-eastern Estonia) are performed using the models HILATAR (regional scale) and AEROPOL (local scale). The modelling results are compared with air quality monitoring results from the observation stations in the Baltic Sea region and with the results of snow pollution study in Estonia. It was found, that although the bulk of the ash emitted is deposited near the sources, the emissions are large enough to create remarkable background deposition in the Baltic Sea region. The uncertainties related to the effective particle size are discussed and corresponding sensitivity studies are performed.     

Phosphorus speciation in sediments from the Baltic Sea,evaluated by a multi-method approach

Journal of Soils and Sediments - Phosphorus (P) is a crucial element for living organisms at both land and sea, but simultaneously, it can cause environmental problems especially in marine...     

An Estimation of the Potential Fluxes of Nitrogen Phosphorus, Cadmium and Lead from Sea Ice and Snow in the Northern Baltic Sea

The amount of nutrients (N and P) and trace elements (Cd and Pb)accumulated and incorporated into the snow and sea ice cover was assessed for the northern Baltic Sea, resulting in an estimate for the potential flux of nutrients and trace elements to underlying waters during sea ice and snow melt. From the atmosphere the sea ice and snow cover accumulate less than 3% of the annual N and P load, and about 5% of the annual Cd and Pb load to the Bothnian Bay. The atmospheric deposition of nutrients to the northern Baltic Sea has declined considerably during the last decade. The total accumulation in the snow and ice, from the atmosphere and seawater, make up to 6% of the annual nutrient and up to 40% of the annual Cd and Pb load into the Bothnian Bay. Thus sea ice plays an important, but still poorly understood role in chemical cycling, transformations, and budgets. The fate of substances accumulated and released from snow and sea ice merit further investigation, especially if sea ice is a source and a platform for transformation of accumulated substances, thus indirectly affecting their toxicity and/or bioavailability before they are released to the water column.     

Safety evaluation of organoarsenical species in edible Porphyra from the China Sea

A study was carried out to determine arsenic species in Porphyra seaweed originating from the China Sea. Information about arsenic species in Porphyra was provided by HPLC-ICP-MS and ES-MS-MS. The total arsenic concentrations of Porphyra samples from five different producing areas ranged from 2.1 to 21.6 mg/kg. The analysis report also showed that arsenosugars were the only arsenic species that could be detected in all of the extracts of samples. Arsenosugar PO(4) was the major compound in most samples (0.3-13.9 mg/kg of dry weight), followed by arsenosugar OH (0.7-6.2 mg/kg of dry weight). A further experiment was done to investigate the stability of arsenosugars in the process of being heated. It was observed that the arsenosugars were stable during a short-term heating at 100 degrees C. Their stability in human ingestion was also studied. A substantial increase of dimethylarsinic acid (DMA) was detected in urine samples collected from six volunteers after the consumption of this seaweed. The results obtained indicated that arsenosugars had been metabolized to DMA, which is more toxic than arsenosugars. From this point of view, consumers should consider the possible adverse effects of edible Porphyra on human health and choose those Porphyra having lower arsenic concentrations.     

Retention and Long Term Accumulation of EOCl from Pulp Mill Effluents in a Baltic Sea Recipient

The total inventory and distribution of ExtractableOrganic Chlorine (EOCl) has been investigated in anestuary exposed to pulp mill effluents for over 50 yr.The estuarine turnover of suspended particulate matter(SPM) and associated pollutants was studied using a modeldescribing important processes for EOCl accumulation. Therecipient has a low retention of SPM due to dominatingstratified conditions in the water column. The totalinventory of EOCl in the sediment is therefore relativelylow as compared with the total discharge. It was foundthat the vertical distribution of EOCl has a closerelationship to the extent of chlorine use at the mill.Discharges of SPM from the pulp production process play amajor role in establishing the chronology of the sediment.A modernisation of the mill from 1986 to 1991 considerablyreduced the discharges of chlorinated substances. In the near future there will be an accumulation of EOCl in the estuary.     

Pre-harvest sprouting tolerance of different winter triticale cultivars in the Baltic Sea area

Abstract

Experiments were carried out to investigate 10 winter triticale cultivars for 1) genetic variability of patterns of resistance to pre-harvest sprouting, and 2) the simultaneity of seed maturation in spikes by determining the developmental stage and by measuring the rate of germination before and after physiological maturity. The cultivars used were Dagro, Fidelio, Lamberto, Lasko, Lupus, Modus, Prego, Tewo, Ulrika and Vision, and were compared by measuring the post-harvest grain falling number and by germination tests on harvested spikes during the grain filling period. Winter rye Vambo and winter wheat Kosack were used as controls. The moisture content of kernels at physiological maturity (PM) was affected by climatic conditions (r=0.38; p<0.05). Germination rate of kernels in spike before PM was influenced by cultivar only up to 17%; mostly it was affected by climatic conditions (coefficient of determination, 54%). Kernel germination rate after PM was dependent on cultivar up to 37%, but was dependent on precipitation amounts in August (coefficient of determination, 60%). The most resistant cultivar to germination during post-physiological maturity period was Modus, followed by Dagro and Prego. Kernels’ germination rate after PM was found to be an appropriate measure for selection of promising triticale cultivars for the climatic conditions, which are specific for the locations studied. The desiccation rate after PM affected significantly the duration of the period from PM up to harvest time (r=?0.50; p<0.01).     

Sublethal effects of insect growth regulators upon crab larval behavior

Both swimming speeds and phototaxis by the four larval stages of the crab Rhithropanopeus harrisii were monitored upon chronic exposure to sublethal concentrations of the insect growth regulators methroprene (Altosid^R: ZR-515), hydroprene (Altozar^R: ZR-512) and dimiline (TH-6040). Larvae were reared under conditions of salinity (20orbo) and temperature (25°C) which produce the greatest developmental success. Sublethal concentrations of methroprene had no effect on swimming rates or phototaxis as compared to the acetone control larvae. For hydroprene, swimming rates by stage I, II and III zoeae were unaffected while a significant increase in swimming speeds occurred in Stage IV zoeae exposed to concentrations of 0.05 and 0.1 ppm. Only Stage III zoeae exposed to 0.l ppm showed a significant decrease in the level of positive phototaxis. Dimilin was much more potent, as significant increases in swimming speeds occurred in Stage I, II and III zoeae, with 0.3 ppb being the lowest effective concentration. Although swimming by Stage IV zoeae was unaffected, phototaxis was altered at concentrations as low as 0.1 ppb. Concentrations, which alter behavior, are related to levels which are reported to control mosquitoe larvae.     

Effects of feral mink removal on seabirds, waders and passerines on small islands in the Baltic Sea

We studied the effects of removing introduced American mink (Mustela vison) on the number of birds breeding on small islands in the Baltic Sea. During autumn 1992-2001 mink were removed from a 72 km² area, while mink were not removed from a 35 km² control area. Second removal (125 km²) and control areas (130 km²) were established during 1998-2001. The breeding densities of ringed plover (Charadrius hiaticula), arctic skua (Stercorarius parasiticus), arctic tern (Sterna paradisaea) and rock pipit (Anthus petrosus) increased markedly in the removal areas in comparison to the control areas. Turnstone (Arenaria interpres), common gull (Larus canus) and wheatear (Oenanthe oenanthe) also appeared to increase. Two species already extinct in one of the removal areas, razorbill (Alca torda) and black guillemot (Cepphus grylle), returned to breed in the area. Breeding densities of great black-backed gull (Larus marinus), oystercatcher (Haematopus ostralegus) and white wagtail (Motacilla alba) were unaffected. We conclude that it is possible to remove feral mink from large archipelagos with many small islands, and that mink removal increases the breeding densities of many bird species in this habitat.     

Sublethal effects of imidacloprid on the burrowing behaviour of two earthworm species: Modifications of the 3D burrow systems in artificial cores and consequences on gas diffusion in soil

Earthworms have been termed ‘ecosystem engineers’ (sensu [Jones, C.G., Lawton, J.H., Shachak, M., 1994. Organisms as ecosysem engineers. Oikos 69, 373-386.]) because of the important roles they play in the soil. As a consequence, it is assumed that if earthworms change their behaviour following exposure to pesticides or pollutants this could have a drastic impact on soil functioning. To test this assumption under laboratory conditions, we studied the burrow systems made by two earthworm species (the anecic Aporrectodea nocturna and the endogeic Allolobophora icterica) in artificial soil cores containing imidacloprid, a widely used neonicotinoid insecticide. After 1-month incubation period, the macropores created in the soil core were analyzed by tomography. In order to further characterize transfer properties associated with burrow systems gas diffusion measurements were also carried out. The burrow systems made by the two earthworm species were very different: A. nocturna made more continuous, less branched, more vertical and wider burrows than A. icterica. Some changes to A. nocturna burrow systems were observed after exposure to imidacloprid (they made a smaller burrow system and burrows were more narrow), but only at the highest concentration of imidacloprid used (0.5 mg kg⁻¹). A. icterica worms were more sensitive to imidacloprid and many differences in their burrow systems (length, sinuosity, branching rate and number of burrows) were observed at both concentrations tested (0.1 and 0. 5 mg kg⁻¹). As a consequence, the continuity of the burrow systems made by both species was altered following imidacloprid treatment. Gas diffusion through the A. nocturna soil cores was reduced but no difference in gas diffusion was observed in the A. icterica soil cores.     

Variation in seed oil composition of species from the genera Barbarea and Lepidium

The seed oil composition and content in a number of accessions from species of the genera Barbarea and Lepidium were analysed. The oil from most accessions of B. verna contained more than 50% erucic acid, while the oil from B. vulgaris contained ～ 30% erucic acid, and 22% each of oleic and linoleic acid. The oil from B. intermedia resembled that of B. verna. The oil content was ～ 30% in all three species. The oil composition of L. campestre and L. heterophyllum is ～ 35% linolenic acid and 23% erucic acid. Other Lepidium species had up to 47% linolenic acid in the oil. The oil content of L. campestre and L. heterophylhim was just below 20%, but other species had more than 30% oil in their seeds. The variation in oil composition found within and between species is considered sufficient for the breeding of valuable oil qualities in both genera.     

Sublethal effects of nickel on carbohydrate metabolism,blood and mineral contents of Tilapia nilotica

Effects of three sublethal levels (19.2, 32 and 51.2 mg L^?1) of Ni on carbohydrate metabolism, hematology and mineral contents of Tilapia nilotica at 6 time intervals from 6 to 96 hr have been evaluated. Prominent dose-dependent hyperlacticemia and hyperglycemia were showed at the three Ni levels. Liver glycogen showed a general decrease at all Ni levels and muscle glycogen showed a decrease only at the two higher levels of Ni. High Levels of Ni elevated red blood cell count, hemoglobin content and packed cell volume and caused leucopenia and lymphopenia. The presence of Ni resulted in its accumulation in the blood, kidney, liver and muscle. Nickel accumulated to the greatest extent in the kidney. It had no statistical influence on the blood Cu content but considerably increased the Zn content of blood and Fe content of all the tissues investigated.     

Bycatches of common guillemot (Uria aalge) in the Baltic Sea gillnet fishery

Bycatch of common guillemots (Uria aalge) appears to be the single most serious threat to the population, and the proportion of recoveries of ringed birds in fishing gear, compared with other finding circumstances, has significantly increased during a 28 year period (P<0.01). Out of 1952 ringed common guillemots reported found between 1972 and 1999 in the Baltic Sea, 980 (50.2%) were caught in fishing gear. The bycatch in set gillnets for cod (Gadus morhua) constituted 22.3%, drift gillnets for salmon (Salmo salar) 65.5%, and other fishing gear 12.2%. The proportion of recoveries in cod gillnets has significantly increased during the study period (P<0.05), while no clear trend was observed in the recoveries in salmon gillnets. The Swedish fishing effort follows a similar pattern for cod but has decreased for salmon. The observed increased use of cod gillnets in the Baltic Sea may have contributed to the observed decrease in adult survival rate, and we provide two different estimates suggesting that significant proportions of the guillemot population are caught annually in the Baltic Sea gillnet fishery. We suggest several available techniques to reduce bycatch in the Baltic Sea fishery.     

菜籽挤压膨化系统参数对出油率影响的试验研究

该文研究了用于浸油的一种菜籽挤压膨化预处理工艺(油菜籽清理—带壳粉碎—膨化—浸油)的可行性，油菜籽挤压膨化系统参数(模孔孔径、套筒温度、物料含水率、螺杆转速)对各考察指标(粕的残油率、膨化物含油率及榨笼出油率)的影响规律，挤压膨化系统优化参数的范围为模孔孔径8～12 mm、套筒温度105～125℃、物料含水率6.6%、螺杆转速35～55 r/min。研究表明：只要参数选择合适，带壳油菜籽清理、粉碎、挤压膨化、浸出的菜籽浸油预处理工艺是可行的，且残油率较低。该菜籽挤压膨化浸油预处理工艺可供生产参考。     

Experimental study of the effect of oil on some representatives of benthos in the Caspian Sea

Experimental studies of the influence of crude oil on the bottom fauna of the Caspian Sea were carried out in 1970-1971 at Artem Island 86 km from Baku. The investigated species on the sensitivity to oil contamination are divided into 3 groups: more sensitive species —Ch. albidus; the sensitive -C. lamarcki, N. elinguis; and less sensitive species —N. diversicolor, P. dubia andA. ovata. Under high concentrations of oil (higher than 3 to 5 mg1^?1) the animals initially do not change weight and then they lose weight and perish. In a weak solution of oil (below 1 mg^?1) a speed up in normal evolution, growth, and reproduction took place in the animals.     

Gamma-linolenic acid and tocopherol contents in the seed oil of 47 accessions from several Ribes species

Gamma-linolenic acid is an essential fatty acid for humans with delta-6-desaturase deficiency; it is a precursor of prostaglandins, prostacyclins, and tromboxanes; and it has antiinflammatory and antitumoral effects. Tocopherols are natural antioxidants with biological activity, heart/vascular, and cancer protective properties. The oil, gamma-linolenic acid, and tocopherol contents, as well as tocopherol composition, were investigated in the seed oil of a collection of 47 accessions belonging to various species of the genus Ribes. Differences for oil content among species were not significant. The highest total tocopherol content was found in R. nigrum (mean, 1716 mg kg(-1) oil), followed by R. rubrum (mean, 1442 mg kg(-1) oil). R. grossularia showed the lowest values for this trait (mean, 786 mg kg(-1) oil). The three species also differed strongly for tocopherol composition. R. rubrumwas distinguished by a higher concentration of delta-tocopherol (mean, 20.2%); R. grossularia displayed the highest percentage of gamma-tocopherol (mean, 70.0%), and R. nigrum showed the highest concentration for alpha-tocopherol (mean, 34.8%), the most biologically active among the four tocopherols. Regarding gamma-linolenic acid, the highest content was found in R. nigrum, which exhibited up to 15.8% of this essential fatty acid in the oil. R. grossularia and R. rubrum showed mean gamma-linolenic acid contents of 8% and 6.2%, respectively. The present study indicated that seeds of Ribes species, especially R. nigrum, could be used as sources of gamma-linolenic acid and natural vitamin E.     

Composition and settling properties of suspended particulate matter in estuaries of the Chesapeake Bay and Baltic Sea regions

Purpose

Our goal was to understand how differences in source material (allochthonous vs. autochthonous) and phytoplankton communities (diatoms vs. cyanobacteria) influence composition and settling properties of suspended particulate matter.

Materials and methods

We characterized the composition and settling properties of suspended particulate matter in two systems—one which has a high hydrologic loading factor (watershed to surface area ratio), and a diatom-dominated phytoplankton community (James River Estuary, USA), and a second, where hydrologic inputs are proportionally smaller, and the summer phytoplankton community is  dominated by cyanobacteria (Curonian Lagoon, Lithuania).

Results and discussion

In the James, we found that TSS concentrations were positively related to discharge, whereas POC concentrations were negatively correlated with discharge and positively correlated with Chl-a. We infer that suspended particulate matter in this system was largely derived from allochthonous inputs, but that the organic matter fraction was derived from autochthonous production. In the Curonian Lagoon, TSS concentrations were correlated with Chl-a, but not discharge, indicating that suspended particulate matter was largely of autochthonous origin. In the James, the proportion of settleable materials was greater during high TSS concentrations, indicating that high discharge events delivered heavier particulates. In the Curonian Lagoon, we observed a seasonal decline in settling rates associated with the shift from mixed (diatoms and chlorophytes) to cyanobacteria-dominated phytoplankton, which we attribute to the presence of positively buoyant cyanobacteria.

Conclusions

We found that a comparative approach yielded useful insights regarding sources, composition, and settling properties of suspended particulate matter in two estuaries that differ in hydrologic loading and phytoplankton community composition. Our findings suggest that the presence of positively buoyant cyanobacteria favors export losses of particulate C, N, and P to marine waters over retention through sedimentation in transitional zones.

     

Tree species effects on microbial respiration from decomposing leaf and fine root litter

Tree species have an impact on decomposition processes of woody litter, but the effects of different tree species on microbial heterotrophic respiration derived from decomposing litter are still unclear. Here we used leaf and fine root litter of six tree species differing in chemical and morphological traits in a temperate forest and elucidated the effects of tree species on the relationships between litter-derived microbial respiration rates and decomposition rates and morphological traits, including specific leaf area (cm² g⁻¹) and specific root length (m g⁻¹) of litter at the same site. Litterbags set in forest soil were sequentially collected five times over the course of 18 months. During litter decomposition, microbial respiration from leaf and fine root litter differed among the six tree species. Temporal changes in the remaining mass and morphology (specific leaf area and specific root length) were observed, and the magnitude of these changes differed among species. Positive correlations were observed between respiration and mass loss or morphology across species. These results revealed that litter mass loss and morphological dynamics during decomposition jointly enhanced microbial respiration, and these carbon-based litter traits explained species differences in decomposition of leaves and fine roots. In conclusion, tree species influenced the magnitude and direction of microbial respiration during leaf/fine root litter decomposition. Tree species also affected the relationship between microbial respiration and litter decomposition through direct effects of litter traits and indirect effects mediated by regulation of heterotroph requirements.     

Sediment Accumulation of Nutrients (N, P) in the Eastern Gulf of Finland (Baltic Sea)

Dry weight (DW), ignition loss (IL) and concentrations of total nitrogen (TN) and total phosphorus (TP) of the sediment surface layer (0 to 10 cm, 1 cm slices) were analyzed from 20 sites in the eastern Gulf of Finland. The distance of the sampling sites from the mouth of the River Neva explained the nutrient concentrations of the sediments well, while the effect of water depth was negligible. The increase of TN and the decrease of TP along the transect from the river mouth towards the open Gulf were caused by the diminishing share of allochthonous material supplied from the River Neva. The mean TN concentration of the different accumulation areas was about 40 % higher in the sediment surface than in the deeper layer (9 to 10 cm). The corresponding difference for TP varied from 53 to 56 %. The results suggest considerable netflux of nutrients from sediment to water. The net sediment accumulation of nutrients were estimated as 6.0 g m-2 a-1 of N and 1.7 g m-2 a-1 of P corresponding 22 000 t a-1 of N and 6 100 t a-1 of P for the whole eastern Gulf.