Anthropogenic underwater noise: A review on physiological and molecular responses of marine biota.

The detrimental effects of anthropogenic underwater noise on marine organisms have garnered significant attention among scientists. This review delves into the research concerning the repercussions of underwater noise on marine species, with specific emphasis on the physiological and molecular responses of marine biota. This review investigates the sensory mechanisms, hearing sensitivity, and reaction thresholds of diverse marine organisms, shedding light on their susceptibility to underwater noise disturbances. The physiological and molecular effects of anthropogenic underwater noise on marine biota include oxidative stress, energy homeostasis, metabolism, immune function, and respiration. Additionally, changes in the gene expression profile associated with oxidative stress, metabolism, and immunological response are among the responses reported for marine biota. These effects pose a threat to animal fitness and potentially affect their survival as individuals and populations.

Decreased surface and bottom salinity and elevated bottom temperature in the Northern Baltic Sea over the past six decades.

Temperature and salinity are key factors in controlling marine habitats and gas fluxes. Finnish and Swedish temperature and salinity monitoring data from the northern Baltic Sea since the 1960s, and Argo buoy data from the eastern Gotland Basin and the Bothnian Sea from 2012 to 2021 were examined using linear trend analysis. Since the 1960's near-bottom temperature has increased by 0.75-2.9 °C (0.013-0.115 °C/a) and surface salinity declined by 0.31-1.14 units (0.005-0.019/a). Surface temperature trends at monitoring stations were negative (16 cases out of 33) but deemed unreliable. Near-bottom salinity has declined by 0.35-1.45 units (0.007-0.025/a), except in the northern Baltic Proper and the central-eastern Gulf of Finland. Most rapid increases in near-bottom temperature have occurred after 1993, especially in the northern Baltic Proper and the Gulf of Finland. Argo data corroborated declining surface salinity in the eastern Gotland Basin, increasing deep-water temperature in the eastern Gotland Basin and the Bothnian Sea and increasing deep-water salinity in the eastern Gotland Basin. Argo data from 2013 to 2021 indicated deep-water temperature increase in the Gotland basin was more rapid than the concomitant salinity increase and is probably related to global change.

Polycyclic aromatic hydrocarbon sorption and bacterial community composition of biodegradable and conventional plastics incubated in coastal sediments.

Resistant to degradation, plastic litter poses a long-term threat to marine ecosystems. Biodegradable materials have been developed to replace conventional plastics, but little is known of their impacts and degradation in marine environments. A 14-week laboratory experiment was conducted to investigate the sorption of polycyclic aromatic hydrocarbons (PAHs) to conventional (polystyrene PS and polyamide PA) and bio-based, biodegradable plastic films (cellulose acetate CA and poly-L-lactic acid PLLA), and to examine the composition of bacterial communities colonizing these materials. Mesoplastics (1 cm2) of these materials were incubated in sediment and seawater collected from two sites in the Gulf of Finland, on the coast of the highly urbanized area of Helsinki, Finland. PS sorbed more PAHs than did the other plastic types at both sites, and the concentration of PAHs was consistently and considerably smaller in plastics than in the sediment. In general, the plastic bacterial biofilms resembled those in the surrounding media (water and/or sediment). However, in the sediment incubations, the community composition on CA diverged from that of the other three plastic types and was enriched with Bacteroidia and potentially cellulolytic Spirochaetia at both sites. The results indicate that certain biodegradable plastics, such as CA, may harbour potential bioplastic-degrading communities and that PAH sorption capacity varies between polymer types. Since biodegradable plastics are presented as replacements for conventional plastics in applications with risk of ending up in the marine environment, the results highlight the need to carefully examine the environmental behaviour of each biodegradable plastic type before they are extensively introduced to the market.

Rapid and Highly Sensitive Non-Competitive Immunoassay for Specific Detection of Nodularin.

Nodularin (NOD) is a cyclic penta-peptide hepatotoxin mainly produced by Nodularia spumigena, reported from the brackish water bodies of various parts of the world. It can accumulate in the food chain and, for safety reasons, levels of NOD not only in water bodies but also in food matrices are of interest. Here, we report on a non-competitive immunoassay for the specific detection of NOD. A phage display technique was utilized to interrogate a synthetic antibody phage library for binders recognizing NOD bound to an anti-ADDA (3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4(E),6(E)-dienoic acid) monoclonal antibody (Mab). One of the obtained immunocomplex binders, designated SA32C11, showed very high specificity towards nodularin-R (NOD-R) over to the tested 10 different microcystins (microcystin-LR, -dmLR, -RR, -dmRR, -YR, -LY, -LF, -LW, -LA, -WR). It was expressed in Escherichia coli as a single chain antibody fragment (scFv) fusion protein and used to establish a time-resolved fluorometry-based assay in combination with the anti-ADDA Mab. The detection limit (blank + 3SD) of the immunoassay, with a total assay time of 1 h 10 min, is 0.03 µg/L of NOD-R. This represents the most sensitive immunoassay method for the specific detection of NOD reported so far. The assay was tested for its performance to detect NOD using spiked (0.1 to 3 µg/L of NOD-R) water samples including brackish sea and coastal water and the recovery ranged from 79 to 127%. Furthermore, a panel of environmental samples, including water from different sources, fish and other marine tissue specimens, were analyzed for NOD using the assay. The assay has potential as a rapid screening tool for the analysis of a large number of water samples for the presence of NOD. It can also find applications in the analysis of the bioaccumulation of NOD in marine organisms and in the food chain.

Results of a Saxitoxin Proficiency Test Including Characterization of Reference Material and Stability Studies.

A saxitoxin (STX) proficiency test (PT) was organized as part of the Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk (EQuATox) project. The aim of this PT was to provide an evaluation of existing methods and the European laboratories' capabilities for the analysis of STX and some of its analogues in real samples. Homogenized mussel material and algal cell materials containing paralytic shellfish poisoning (PSP) toxins were produced as reference sample matrices. The reference material was characterized using various analytical methods. Acidified algal extract samples at two concentration levels were prepared from a bulk culture of PSP toxins producing dinoflagellate Alexandrium ostenfeldii. The homogeneity and stability of the prepared PT samples were studied and found to be fit-for-purpose. Thereafter, eight STX PT samples were sent to ten participating laboratories from eight countries. The PT offered the participating laboratories the possibility to assess their performance regarding the qualitative and quantitative detection of PSP toxins. Various techniques such as official Association of Official Analytical Chemists (AOAC) methods, immunoassays, and liquid chromatography-mass spectrometry were used for sample analyses.

Cumulative effects of exposure to cyanobacteria bloom extracts and benzo[a]pyrene on antioxidant defence biomarkers in Gammarus oceanicus (Crustacea: Amphipoda).

The Baltic Sea suffers from extensive blooms of the toxic cyanobacteria Nodularia spumigena that produces nodularin toxin (NOD). Additionally, intensification of oil transportation and related activities in the area increase the risk of oil spills. The current experiment was designed to mimic a situation where an oil spill occurs during a cyanobacterial bloom by exposing the amphipod Gammarus oceanicus to a NOD-rich cyanobacterial extract and the polycyclic aromatic hydrocarbon compound benzo[a]pyrene (B[a]P), a common constituent of oil. The activity of the antioxidant enzymes glutathione S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) were examined after 48 and 96 h of exposure. Exposure to low and high levels of the NOD-rich extract produced a time-dependent activation of GST, GPx and SOD. CAT levels were elevated only by high NOD treatment. Also the toxicity of B[a]P was indicated by significantly elevated antioxidant response. In the combined exposures treatment-dependent additive increases in the activity of GPx and SOD were observed as well as inhibitory (antagonistic) effects on GST, CAT and GPx. Rapid concentration-dependent accumulation of NOD by G. oceanicus was observed. The addition of B[a]P reduced the accumulation of NOD and resulted in different biomarker response patterns compared to single exposures demonstrating the effects of mixture toxicity.

Sedimentation of PCDD/Fs and PCBs in the Gulf of Finland and the Gulf of Bothnia, the Baltic Sea.

Sediment trap material was collected during May-December in the period 1996-2008 in three coastal areas and four open sea stations in the Finnish territory of the Baltic Sea. The highest sedimentation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with a typical source-related congener profile from chlorophenol production dominated by highly chlorinated dibenzofurans was found close to a historical source in the Kymijoki estuary. This was an order of magnitude higher than in other river estuaries and two orders of magnitude higher than in the open sea stations. The sedimentation of polychlorinated biphenyls (PCBs) was also higher in river estuaries than in other areas. No significant decrease over a 12 year period of monitoring was found in concentration or in sedimentation in the Kymijoki estuary. In the western Gulf of Finland, the Archipelago Sea and the Gulf of Bothnia, the dominating congeners, calculated as toxic equivalent (TEQ) in sedimentation were 1, 2, 3, 7, 8-PeCDD and 2, 3, 4, 7, 8-PeCDF, often reported as the main congeners in deposition.

Speciation of ¹²9I in sea, lake and rain waters.

Concentrations of the very long-lived fission product (129)I and stable iodine ((127)I) in the Baltic Sea and lake and rain waters from Finland, were measured as well as their occurrence as iodide (I(-)) and iodate (IO(3)(-)). The highest concentrations of both (127)I and (129)I occurred in sea water, on average 11.1 ± 4.3 µg/l and 3.9 ± 4.1 × 10(-9) at/l. In rain and lake waters the concentration of (129)I was more or less identical and almost one order of magnitude lower than in sea water. Based on these observations, and data from the literature, it is assumed that the source of (129)I in lakes is precipitation and the major source in the Baltic Sea is the inflow of sea water from the North Sea through the Danish Straits. The concentration of (129)I in the Baltic Sea has increased by a factor of six during ten years from 1999. In all studied water types the main chemical form of both iodine isotopes was iodide; in sea and lake waters by 92-96% and in rain water by 75-88%. Compared to (127)I the fraction of iodide was slightly higher in case of (129)I in all waters.

[Harmful algae and health]. / Haitalliset levät ja terveys.

Harmful algae are a worldwide problem. Phycotoxins is a general term for toxic compounds produced by harmful species of the phytoplankton. This review deals with the occurrence of harmful algae and phycotoxins in the Baltic Sea and other domestic waters, the ways of getting exposed to them, and their effects. Advice on how to avoid the exposure is provided.

Spatially differing bacterial communities in water columns of the northern Baltic Sea.

The Baltic Sea is a large, shallow, and strongly stratified brackish water basin. It suffers from eutrophication, toxic cyanobacterial blooms, and oxygen depletion, all of which pose a threat to local marine communities. In this study, the diversity and community structure of the northern Baltic Sea bacterial communities in the water column were, for the first time, thoroughly studied by 454 sequencing. The spring and autumn bacterial communities were one order of magnitude less diverse than those in recently studied oceanic habitats. Patchiness and strong stratification were clearly detectable; <1% of operational taxonomic units were shared among 11 samples. The community composition was more uniform horizontally (at a fixed depth) between different sites than vertically within one sampling site, implying that the community structure was affected by prevailing physical and hydrochemical conditions. Taxonomic affiliations revealed a total of 23 bacterial classes and 169 genera, while 5% of the sequences remained unclassified. The cyanobacteria accounted for <2% of the sequences, and potentially toxic cyanobacterial genera were essentially absent during the sampling seasons.

Microbial responses to mustard gas dumped in the Baltic Sea.

Microbiological studies were carried out on chemical weapon dump sites in the Baltic Sea. The effect of mustard gas hydrolysis products (MGHPs) on marine microbiota and the ability of microorganisms to degrade MGHPs were studied. Many stations at the dump sites demonstrated reduced microbial diversity, and increased growth of species able to use mustard gas hydrolysis products as sole source of carbon. Significant amounts of MGHP-degrading bacteria were revealed in the near-bottom water. The MGHP-degrading microorganisms identified as Achromobacter sp., Pseudomonas sp., and Arthrobacter sp. were isolated. These microorganisms were capable of utilizing the major product of hydrolysis, thiodiglycol, as the sole source of carbon and energy. The bacteria were capable of metabolizing MGHPs at a low temperature. The metabolic pathway for thiodiglycol degradation was proposed. The results suggest the potential for MGHPs biodegradation by naturally occurring populations of near-bottom-water and sediment microorganisms.

Production and sedimentation of peptide toxins nodularin-R and microcystin-LR in the northern Baltic Sea.

This seven-year survey was primarily targeted to quantification of production of nodularin-R (NOD-R), a cyclic pentapeptide hepatotoxin, in Baltic Sea cyanobacteria waterblooms. Additionally, NOD-R and microcystin-LR (MC-LR; a cyclic heptapeptide toxin) sedimentation rates and NOD-R sediment storage were estimated. NOD-R production (70-2450 microg m(-3); approximately 1 kg km(-2) per season) and sedimentation rates (particles; 0.03-5.7 microg m(-2)d(-1); approximately 0.3kg km(-2) per season) were highly variable over space and time. Cell numbers of Nodularia spumigena did not correlate with NOD-R quantities. Dissolved NOD-R comprised 57-100% of total NOD-R in the predominantly senescent, low-intensity phytoplankton blooms and seston. Unprecedentedly intensive MC-LR sedimentation (0.56 microg m(-2)d(-1)) occurred in 2004. Hepatotoxin sedimentation rates highly exceeded those of anthropogenic xenobiotics. NOD-R storage in surficial sediments was 0.4-20 microg kg(-1) ( approximately 0.1 kg km(-2)). Loss of NOD-R within the chain consisting of phytoplankton, seston and soft sediments seemed very effective.

Accumulation and depuration of cyanobacterial toxin nodularin and biomarker responses in the mussel Mytilus edulis.

Blue mussels (Mytilus edulis) were exposed to an extract made of natural cyanobacterial mixture containing toxic cyanobacterium Nodularia spumigena (70-110 microg nodularin l(-1), 24-h exposure followed by 144-h depuration period in clean water). Toxin concentration increased from initial 400 to 1100 mg kg(-1) after 24-h exposure, measured by liquid chromatography/mass spectrometry (LC/MS). Acetylcholinesterase activity (AChE), a biomarker of direct neurotoxic effects, showed inhibition after 12 and 24h exposure but returned to control level during the depuration period. Catalase (CAT) activity, an indicator of oxidative stress, showed significantly elevated levels in exposed mussels but only 72 h after the end of the exposure. No change in the activity of glutathione-S-transferase (GST) involved in conjugation reactions could be observed. A gradual yet incomplete elimination of nodularin (from 1100 to 600 mg kg(-1)) was observed during the depuration period, and the tissue levels were 30% lower in clean water after 24 h. The observed increase in oxidative stress indicated by elevated CAT activity is likely connected to detoxification reactions leading to the production of reactive oxygen species, including an apparent time lag in this specific enzymatic defence response. That no change in GST activity was observed suggests that this enzyme is not significantly involved in the detoxification process of nodularin-containing cyanobacterial extract in M. edulis.

Nodularin induces oxidative stress in the Baltic Sea brown alga Fucus vesiculosus (Phaeophyceae).

In the Baltic Sea regular, intensive cyanobacterial blooms rich in the cyanobacterium Nodularia spumigena occur during the summer season. N. spumigena is known to produce the cyclic pentapeptide nodularin (NOD) in high concentrations. Marine macroalgae, together with sea-grass meadows, are an extremely important habitat for life in the sea. In addition to this, the decaying macroalgae substantially contribute to the substrate for the microbial loop in coastal food webs. Uptake of nodularin into the brown macroalga Fucus vesiculosus was assessed using an ELISA technique resulting in an uptake of up to 45.1 microg kg(-1) fresh weight (fw). Nodularin was also detected in the reproductive part of the algae (receptacle) at 14.1 microg kg(-1) fw. The induction of oxidative stress in F. vesiculosus, after exposure to NOD, was also shown by monitoring cellular damage as changes in lipid peroxidation and the activation of antioxidative defence systems (antioxidative capacity, superoxide dismutase and soluble glutathione S-transferase).

Activity and substrate specificity of cytosolic and microsomal glutathione S-transferase in Australian black tiger prawns (Penaeus monodon) after exposure to cyanobacterial toxins.

Cyanobacterial toxins have been shown to have a far-reaching impact-from aquatic organisms to human health. Aquatic organisms are typically exposed in their natural environment to toxic cyanobacteria, and exposure can occur via ingestion of cyanobacterial cells or by bioaccumulation of water-borne toxin. The aquaculture and fisheries of crustaceans are among the most important seafood industries. Concomitant with the growth of this industry, the importance of the health of crustaceans increased. The black tiger prawn is the major cultivated prawn in Australia. The aquaculture of these prawns takes place in shallow ponds, where blooms, often of cyanobacteria, develop. Cyanobacterial toxins were hypothesized to contribute to the mortality of prawns. Many aquatic organisms have the possibility of detoxifying cyanobacterial toxins via conjugation to glutathione. The presence of several classes of the cytosolic glutathione S-transferase system in black tiger prawns-mu, pi, theta, alpha, and tau-was shown using different substrates for measurement. Injection experiments with microcystin-LR and feeding experiments with nodularin revealed elevation of GST activity in different types of prawn tissue in parallel with reduction in the GST classes. Correlation analyses of toxin content of the prawns with GST activity showed that low toxin content was correlated with high elevation of enzymes and high toxin content with low elevation of enzymes.

Cyanobacteria and prawn farming in northern New South Wales, Australia--a case study on cyanobacteria diversity and hepatotoxin bioaccumulation.

Harmful cyanobacteria pose a hazard to aquatic ecosystems due to toxins (hepatotoxic microcystins, nodularins, and cylindrospermopsin) they produce. The microcystins and nodularins are potent toxins, which are also tumor promoters. The microcystins and nodularins may accumulate into aquatic organisms and be transferred to higher trophic levels, and eventually affect vector animals and consumers. Prawn farming is a rapidly growing industry in Australia. Because information regarding effects of cyanobacteria at prawn farms was lacking, we examined diversity of cyanobacteria and toxin production plus bioaccumulation into black tiger prawns (Penaeus monodon) under both field (northern New South Wales, Australia, December 2001-April 2002) and laboratory conditions. Samples were analyzed for hepatotoxins using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC). The maximum density of cyanobacteria (1 x 10(6) to 4 x 10(6) cells/l) was reached in April. Cyanobacteria encountered were Oscillatoria sp. (up to 4 x 10(6) cells/l), Pseudanabaena sp. (up to 1.8 x 10(6) cells/l), Microcystis sp. (up to 3.5 x 10(4) cells/l), and Aphanocapsa sp. (up to 2 x 10(4) cells/l). An uncommon cyanobacterium, Romeria sp. (up to 2.2 x 10(6) cells/l), was also observed. Contrasting earlier indications, toxic Nodularia spumigena was absent. Despite that both Oscillatoria sp. and Microcystis sp. are potentially hepatotoxic, hepatotoxin levels in phytoplankton samples remained low (up to 0.5-1.2 mg/kg dw; ELISA) in 2001-2002. ELISA was found suitable not only for phytoplankton but prawn tissues as well. Enzymatic pretreatment improved extractability of hepatotoxin from cyanobacteria (nodularin from N. spumigena as an example), but did not generally increase toxin recovery from prawn hepatopancreas. There were slightly increasing hepatotoxin concentrations in prawn hepatopancreas (from 6-20 to 20-80 microg/kg dw; ELISA) during the study. Hepatotoxin concentrations in surface sediment remained low (<5 microg/kg dw; ELISA) throughout the study. Laboratory experiments indicated that prawn hepatopancreas, heart, and brain were primary organs for hepatotoxin bioaccumulation. Toxin concentration in other organs, including muscle, was less effective. Orally administered nodularin levels in hepatopancreas rapidly decreased from initial 830 to 250 microg/kg dw in 96 h. Similarly, concentration of microcystin-LR injected in prawns decreased from 130 to 30 microg/kg dw (hepatopancreas) in 2 h. These results demonstrate that potential risks caused by cyanobacteria in prawn farming (farmers, prawns, and consumers) were not substantial in 2001-2002. Although prawns may act as vectors for toxin transfer, they did not accumulate alerting amounts of hepatotoxins and were able to effectively detoxify them. Because bloom toxicity may vary, low-frequency toxin monitoring is recommended.

Eiders (Somateria mollissima) obtain nodularin, a cyanobacterial hepatotoxin, in Baltic Sea food web.

Nodularin (NODLN) is a cyclic pentapeptide hepatotoxin produced by the cyanobacterium Nodularia spumigena, which occurs regularly in the Baltic Sea during the summer season. Nodularia blooms have caused several animal kills in the Baltic Sea area, and NODLN has been found in mussels and fish caught from the northern Baltic Sea in 1996 to 2002. We analyzed liver samples of common eider (Somateria mollissima) for NODLN by enzyme-linked immunosorbent assay (ELISA) and liquid chromatography/mass spectrometry (LC-MS). Eiders feed extensively on mussel and can be exposed to NODLN by contaminated mussels. Fifteen eiders were shot and collected from three different sites in the western Gulf of Finland (northern Baltic Sea) in August and September 2002. Analyses by ELISA and LC-MS showed that eider liver samples contained 3 to 180 microg NODLN/kg dry weight and 0.1 to 5.8 microg NODLN/liver (dry wt). This is the first documentation of NODLN in seabirds and additional evidence for the transfer of NODLN in different parts of the Baltic Sea food web.

Accumulation of nodularin-like compounds from the cyanobacterium Nodularia spumigena and changes in acetylcholinesterase activity in the clam Macoma balthica during short-term laboratory exposure.

In this laboratory study the effects of the cyanobacterium Nodularia spumigena (strain AV1) that produces hepatotoxic nodularin (NODLN), non-toxic Nodularia sphaerocarpa (strain UP16f) and purified NODLN on the infaunal clam Macoma balthica from the Baltic Sea were examined. N. sphaerocarpa (2.4 and 12.5 mg dw l(-1)), N. spumigena (4 and 20 mg dw l(-1), intracellular NODLN content ca. 4 and 20 microg l(-1)) and purified NODLN (10 and 50 microg l(-1)) were applied in experimental tanks at 24 h intervals for 96 h. Water samples were taken during the experiment for the measurement of soluble NODLN concentrations. The concentrations of total hepatotoxins in the soft tissues were analysed with enzyme-linked immunosorbent assay (ELISA) and NODLN with high-performance liquid chromatography/diode array detection (HPLC/DAD). Acetylcholinesterase (AChE) activity was measured from the foot tissue samples taken at 0, 24 and 96 h. In the water phase, 60-100% of NODLN in the pure-toxin treatments and all the NODLN in N. spumigena treatments appeared as a yet unidentified form with NODLN-like spectral characteristics. The compound was present in similar quantities also in the non-toxic N. sphaerocarpa treatments. In the toxic N. spumigena treatments the tissue concentration of hepatotoxic NODLN-like compounds (measured with ELISA) increased from the control levels of 0.16 to 16.6 microg g(-1) dw (24 h), reaching 30.3 microg g(-1) dw at 96 h. However, <5% of the toxin detected by ELISA could be shown to be NODLN in HPLC/DAD analysis. Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF/MS) analyses revealed no NODLN-glutathione (GSH) conjugates in the tissues of M. balthica. Combining the responses in the AChE activity recorded after 24 and 96 h exposure, increases by 46% (N. spumigena) and 36% (soluble NODLN) compared with the control activity were observed in the low-level toxic exposures. Oppositely, decreases by 19% (N. spumigena) and 27% (soluble NODLN) of control activity were observed in the high-level exposures. Only the differences between the increased and decreased AChE activities were statistically significant, with individuals exposed to high levels expressing approximately 55% of the activity of those exposed to low concentrations. The results show that M. balthica readily ingests toxic N. spumigena and that accumulation of peptides takes place rapidly, which has potential food chain effects through toxin enrichment. However, it appears that M. balthica is at least partly able to metabolise NODLN. In addition to hepatotoxicity, NODLN seems to induce concentration-dependent neurotoxic effects; this must be taken into consideration when applying AChE activity as a biomarker of specific anthropogenic contamination (e.g. organophosphate and carbamate pesticides).