Natural dissolved humic substances increase the lifespan and promote transgenerational resistance to salt stress in the cladoceran Moina macrocopa

• Published in: Environmental science and pollution research international 2011-07, Vol.18 (6), p.1004-1014
• Main Authors: Suhett, Albert L., Steinberg, Christian E. W., Santangelo, Jayme M., Bozelli, Reinaldo L., Farjalla, Vinicius F.
• Format: Article
• Language: English
• Subjects: Abiotic stress; Animals; Aquatic ecosystems; Aquatic life; Aquatic organisms; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Body length; Carbon; Carbon - analysis; Cladocera - drug effects; Cladocera - growth & development; Dissolved organic carbon; Earth and Environmental Science; Ecosystems; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental impact; Experiments; Female; Humic acids; Humic Substances - analysis; Lagoons; Life history; Life span; Longevity; Male; Models, Animal; Moina macrocopa; Offspring; Organisms; Phenotype; Plankton; Pollutants; Research Article; Salinity; Salts; Stress, Physiological; Studies; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-011-0455-y

Purpose Evidence has accumulated that humic substances (HS) are not inert biogeochemicals. Rather, they cause stress symptoms and may modulate the life history of aquatic organisms. Nevertheless, it is still not clear how HS interact with additional stressors and if their effects are transgenerational. We tested the interactive effects of HS and salt to cladocerans, discussing their consequences for the persistence in fluctuating environments, such as coastal lagoons. Methods We used life-table experiments to test the effects of natural HS from a polyhumic coastal lagoon (0, 5, 10, 20, 50, and 100 mg dissolved organic carbon (DOC) L −1 ) on the life-history of the cladoceran Moina macrocopa. We further tested the effects of HS (10 mg DOC L −1 ), within and across generations, on the resistance of M. macrocopa to salt stress (5.5 g L −1 ). Results HS at 5–20 mg DOC L −1 extended the mean lifespan of M. macrocopa by ~30%. HS also increased body length at maturity by ~4% at 5–50 mg DOC L −1 and stimulated male offspring production at all tested concentrations. Exposure to HS (even maternal only) alleviated the salt-induced reduction of somatic growth. Co-exposure to HS increased body volume by 12–22% relative to salt-only treatments, while pre-exposure to HS increased body volume by 40–56% in treatments with salt presence, when compared to non-pre-exposed animals. Conclusions HS at environmentally realistic concentrations, by acting as mild chemical stressors, modify crucial life-history traits of M. macrocopa , favoring its persistence in fluctuating environments. Some of the effects of HS are even transgenerational.