Marine life | EPFL Graph Search

Marine life, sea life, or ocean life is the plants, animals, and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. Marine organisms, mostly microorganisms, produce oxygen and sequester carbon. Marine life in part shape and protect shorelines, and some marine organisms even help create new land (e.g. coral building reefs). Most life forms evolved initially in marine habitats. By volume, oceans provide about 90% of the living space on the planet. The earliest vertebrates appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians, which spend portions of their lives in water and portions on land. One group of amphibians evolved into reptiles and mammals and a few subsets of each returned to the ocean as sea snakes, sea turtles, seals, manatees, and whales. Plant forms such as kelp and other alga

Prediction and experimental evaluation of soil-water retention behavior of skeletal calcareous soils

Saeed Kouzegaran, Lyesse Laloui

Skeletal calcareous soils refer to soils consisting of skeletal remains of marine organisms. Although calcareous deposits are prevalent along coastal plains throughout the world, there is no study which investigates their behavior in unsaturated conditions. In these conditions, soil-water retention capacity is a fundamental parameter in relation to many geotechnical, environmental, and agricultural aspects. Water retention capacity of a soil is expected to be influenced by intra-particle pores unique to calcareous soils. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) used in the current study clearly revealed this special microstructural characteristic. To study water retention and hydraulic hysteresis behavior of skeletal calcareous soil (obtained from the Hormuz Island of Iran) compared with a reference silicate soil (obtained from the Netherlands), a series of tests were conducted using pressure plate and controlled-suction oedometer apparatuses. Test results showed that in similar grain-size distribution of these soils, water retention curves of calcareous and silica soils are almost the same in low suctions, but calcareous soil retains more water at higher suctions due to its intra-particle voids. In addition, owing to these microstructural pores, ratio of Sr reduction on wetting path of a hysteresis loop was found to be more for calcareous soil than for silicate soil. Besides, to find and/or modify a prediction method for water retention curve of calcareous soil with acceptable accuracy, several existing pedotransfer functions were evaluated. Results showed that models proposed by Zapata et al. (Geotech Spec Publ 99:84–124, 2000) and Saxton et al. (Soil Science Society of America Journal 50(4): 1031–1036, 1986) after some simple modifications provide accurate estimations for water retention curve of calcareous soils.

2020

Immediate Ecotoxicological Effects of Short-Lived Oil Spills on Marine Biota

Jeremy Samuel Arey

Marine environments are frequently exposed to oil spills as a result of transportation, oil drilling or fuel usage. Whereas large oil spills and their effects have been widely documented, more common and recurrent small spills typically escape attention. To fill this important gap in the assessment of oil-spill effects, we performed two independent supervised full sea releases of 5 m(3) of crude oil, complemented by on-board mesocosm studies and sampling of accidentally encountered slicks. Using rapid on-board biological assays, we detect high bioavailability and toxicity of dissolved and dispersed oil within 24 h after the spills, occurring fairly deep (8 m) below the slicks. Selective decline of marine plankton is observed, equally relevant for early stages of larger spills. Our results demonstrate that, contrary to common thinking, even small spills have immediate adverse biological effects and their recurrent nature is likely to affect marine ecosystem functioning.

Nature Publishing Group2016

The emergence of Vibrio pathogens in Europe: ecology, evolution, and pathogenesis (Paris, 11–12th March 2015)

Melanie Blokesch, Frédérique Marie Jeanne Le Roux

Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrioassociated diseases affecting marine organisms such as fish, bivalves and corals. Basic knowledge is still lacking on the ecology and evolutionary biology of these bacteria as well as on their virulence mechanisms. Current limitations in experimental systems to study infection and the lack of diagnostic tools still prevent a better understanding of Vibrio emergence. A major challenge is to foster cooperation between fundamental and applied research in order to investigate the consequences of pathogen emergence in natural Vibrio populations and answer federative questions that meet societal needs. Here we report the proceedings of the first European workshop dedicated to these specific goals of the Vibrio research community by connecting current knowledge to societal issues related to ocean health and food security.

Frontiers Research Foundation2015

Prediction and experimental evaluation of soil-water retention behavior of skeletal calcareous soils

Saeed Kouzegaran, Lyesse Laloui

2020