Introduction to the JES Special Issue on Multiple-Scale Geodynamics of Continental Interiors

A major mission of geosciences is to characterize the composition, structure and geodynamic history of the earth’s continental interiors. Because the evidence for such studies is spread over dif-ferent disciplines and in different spatial and temporal scales, advances in understanding the     

Introduction to the Special Issue on faulting and fault-related processes on planetary surfaces

Faults have been documented on nearly every solid surface in the solar system, from asteroids to moons to planets, and they provide a remarkable suite of data sets and critical problems for investigation and analysis by structural geologists. The lack of significant atmospheres on Mercury, the Moon, and most outer planet satellites, along with slow erosion rates and a lack of crustal recycling and Earth-like plate tectonics on most planetary bodies, allows for excellent preservation of fault scarp morphologies for study of fault populations and developmental sequences.     

Drivers of Change in Shallow Coastal Photic Systems: An Introduction to a Special Issue

Coastal ecosystems are characterized by relatively deep, plankton-based estuaries and much shallower systems where light reaches the bottom. These latter systems, including lagoons, bar-built estuaries, the fringing regions of deeper systems, and other systems of only a few meters deep, are characterized by a variety of benthic primary producers that augment and, in many cases, dominate the production supplied by phytoplankton. These “shallow coastal photic systems” are subject to a wide variety of both natural and anthropogenic drivers and possess numerous natural “filters” that modulate their response to these drivers; in many cases, the responses are much different from those in deeper estuaries. Natural drivers include meteorological forcing, freshwater inflow, episodic events such as storms, wet/dry periods, and background loading of optically active constituents. Anthropogenic drivers include accelerated inputs of nutrients and sediments, chemical contaminants, physical alteration and hydrodynamic manipulation, climate change, the presence of intensive aquaculture, fishery harvests, and introduction of exotic species. The response of these systems is modulated by a number of factors, notably bathymetry, physical flushing, fetch, sediment type, background light attenuation, and the presence of benthic autotrophs, suspension feeding bivalves, and fringing tidal wetlands. Finally, responses to stressors in these systems, particularly anthropogenic nutrient enrichment, consist of blooms of phytoplankton, macroalgae, and epiphytic algae, including harmful algal blooms, subsequent declines in submerged aquatic vegetation and loss of critical habitat, development of hypoxia/anoxia particularly on short time scales (i.e., “diel-cycling”), fish kills, and loss of secondary production. This special issue of Estuaries and Coasts serves to integrate current understanding of the structure and function of shallow coastal photic systems, illustrate the many drivers that cause change in these systems, and synthesize their varied responses.