Shape of Stream Channels Gives Clues to Sediment Size

Sediment size and nutrients regulate denitrification in a tropical stream

Landuse changes might alter N cycling in tropical aquatic ecosystems, but understanding of N cycling in tropical streams is limited. We measured actual and potential denitrification rates during the dry season in Rı́o Las Marı́as, a 4-order Andean piedmont stream in Venezuela. Our objectives were to describe spatial and temporal variation in denitrification, quantify the effects of nutrient avail...

Dorsal stream activation during retrieval of object size and shape.

We investigated dorsal visual stream involvement in the retrieval of a variety of visual attributes of common objects, using functional magnetic resonance imaging. Seven subjects made binary decisions about the shape, color, and size of named objects during scanning. Bilateral parietal activity was significantly greater during retrieval of shape and size information than during retrieval of col...

Benthic Biological Community Responses to Sediment Loading in Experimental Stream Mesocosm Channels

Separating neuronal compartments gives clues as to local effect of ubiquitin conjugates in synaptogenesis

Presynaptic differentiation is a critical and poorly understood step in synapse formation. Using compartmentalized culture systems that isolate axons and nascent synapses, Pinto et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201509039) show that the axonal ubiquitin-proteasome system locally regulates the accumulation of ubiquitinated substrates, triggering presynaptic differentiation.

Stream Insects as Bioindicators of Fine Sediment

Fine inorganic sediment (≤ 2mm) is a major non-point source pollutant in streams. While some fine sediment in streams is natural, loads in human-impacted streams often exceed their capacity to flush these sediments during high flows. Regardless of the source, the negative effects of increased levels of fine sediment in streams are realized in all biotic components of stream ecosystems from micr...