Uptake and Biological Impacts of Miroplastics and Nanoplastics in Sea Squirts

Microplastics have been detected in all marine regions and habitats, from the poles to the deep seas. A number of marine species are known to ingest microplastics, resulting in detrimental impacts. Preliminary work carried out on sea squirts suggested that microplastics may have a negative impact upon their health. Here, the solitary sea squirt, Ciona intestinalis, is used as a model species to observe the impacts of microplastics on sea squirts. This species has a transparent body form and is widely available in coastal waters. Laboratory exposures were carried out using a range of different microplastics; fluorescently labelled polystyrene (PS) and polyamide (PA) microbeads, polyhydroxybutyrate (PHB), low density polyethylene (LPE), polypropylene (PP), nylon fibres (NF), nylon particles (NMP) and polystyrene nanoparticles (PNP), cryo-ground polypropelyne rope fibres, rubber loom bands, high density polyethelyne (HDPE) and polyvinyl chloride (PVC). C. intestinalis ingested all but the cryo-ground rope fibres. Buoyancy is likely to have been an important factor for ingestion by C. intestinalis. Polystyrene and polyamide microbeads were ingested at all concentrations tested (100 and 500 PS beads mL-1, 500 and 1000 PA beads ml-1). However, there were significantly more PS beads in C. intestinalis at 24 hours than at 72 hours. Microplastic egestion was also observed, following ingestion plastics were found to be present in faecal matter. There was no distinct pattern of bead content within the sea squirts or surrounding water with time after removal from plastic contaminated water. C. intestinalis readily ingested microplastics of the tested size ranges, but were able to rapidly eject them without obvious detrimental effects. Wild specimens of C. intestinalis were also analysed for the presence of microplastics. A number of plastic-like particles were found to be present within these organisms, suggesting that ascidians may be susceptible to microplastic ingestion in the marine environment

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Carbon and lipid contents of the copepod Calanus finmarchicus entering diapause in the Fram Strait and their contribution to the boreal and Arctic lipid pump

The boreal copepod Calanus finmarchicus sequesters substantial amounts of carbon (C) in the deep layers of the North Atlantic Ocean through their contribution to the “lipid pump.” This pump is driven by these zooplankton descending from the surface layers to spend prolonged periods at depth during which time they metabolise substantial lipid reserves and a fraction suffer mortality. C. finmarchicus is principally a boreal species but is expatriated by currents flowing northwards into Arctic regions such as the Fram Strait, where it is now able to complete its life cycle. We considered how this expansion to its distributional range adds to the estimated magnitude of the lipid pump. Field sampling in the Fram Strait found C. finmarchicus abundance to be spatially variable with high values, equivalent to those reported for core distributional areas further south, found mainly in the eastern region. Lipid reserve levels were sufficient for many individuals to survive the overwintering period and reproduce the following spring. In accordance with abundance patterns, lipid pump magnitude was greater in the Eastern Fram Strait (2.04 g C m−2 year−1) compared to the Western Fram Strait (0.33 g C m−2 year−1). At least for the eastern region, these rates are similar to those reported for this species elsewhere (average of 4.35 g C m−2 year−1). When extrapolated to the wider spatial area of the Fram Strait, the lipid pump generated by this species in this ocean sector amounts to 0.3 Mt C year−1. Although constituting a modest proportion of the total C. finmarchicus lipid pump of 19.3 Mt C year−1, it indicates that the continued northwards expansion of this species will act to increase the size of its lipid pump, which may counteract that lost through the northwards retreat of its Arctic congeners, Calanus glacialis and Calanus hyperboreus