Onečišćenje, odnosno utjecaj plastike na okoliš, jedan je od globalnih problema današnjice, a poznat je još od davnina. Zbog svoje široke upotrebe plastiku možemo naći u gotovo svim sastavnicama ...okoliša, gdje može štetno utjecati na žive organizme. Plastika, unatoč svojoj praktičnosti, sadrži štetne kemikalije, aditive, poput poput di(2-etilheksil)ftalata (DEHP), mono(2-etilheksil)ftalata (MEHP), bisfenola A (BPA), polikloriranih bifenila (PCB) i drugih. U ovome radu dan je pregled istraživanja štetnog djelovanja aditiva na ekosustav temeljen na raznim testovima toksičnosti.
Diatoms of the genus Pseudo-nitzschia produce domoic acid (DA), a toxin that is vectored in the marine food web, thus causing serious problems for marine organisms and humans. In spite of this, ...knowledge of interactions between grazing zooplankton and diatoms is restricted. In this study, we examined the interactions between Calanus copepodites and toxin producing Pseudo-nitzschia. The copepodites were fed with different concentrations of toxic P. seriata and a strain of P. obtusa that previously was tested to be non-toxic. The ingestion rates did not differ among the diets (P. seriata, P. obtusa, a mixture of both species), and they accumulated 6%-16% of ingested DA (up to 420 µg per dry weight copepodite). When P. seriata was exposed to the copepodites, either through physical contact with the grazers or separated by a membrane, the toxicity of P. seriata increased (up to 3300%) suggesting the response to be chemically mediated. The induced response was also triggered when copepodites grazed on another diatom, supporting the hypothesis that the cues originate from the copepodite. Neither pH nor nutrient concentrations explained the induced DA production. Unexpectedly, P. obtusa also produced DA when exposed to grazing copepodites, thus representing the second reported toxic polar diatom.
We studied how exposure to oil spill response technologies affect marine microorganisms during Arctic winter and spring. Microorganisms were exposed to chemically dispersed oil (DISP), in situ burnt ...oil (ISB), and natural attenuated oil (NATT) in mesocosms from February to May. We subsampled the mesocosms and studied the effects of oil in laboratory incubations as changes in biomass of the major functional groups: bacteria, heterotrophic-nanoflagellates, dinoflagellates, ciliates, pico- and nanophytoplankton, and diatoms over two 14-day periods. In winter, the majority of polycyclic aromatic hydrocarbons (PAHs) remained encapsulated in the ice, and the low concentrations of PAHs in water led to minute changes in biomass of the investigated groups. In spring, however, when the PAHs were partially released from the melting ice, the biomass of many functional groups in DISP and NATT decreased significantly, while the changes in ISB were less pronounced. The overall biomass reduction, as observed in this study, could lead to a disrupted transfer of energy from the primary producers to the higher trophic levels in oil affected areas.
•Oil remediation tools enhance growth of bacteria and heterotrophic nanoflagellates.•In situ burning has the least harmful effects on microbial community structure.•Chemical dispersant and oil weathering reduce microbial community biomass by 50%.
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