An interdisciplinary project to explore the physical, chemical and biological factors that promote the growth of Sargassum blooms in the Tropical Atlantic and investigate the factors that may have changed in recent years (last decade). A novel combination of ecological approaches, remote sensing products, physical modeling, and oceanographic work at sea will be used to investigate and resolve the mechanisms that drive the onset of Sargassum blooms in the Central Tropical Atlantic and their growth and development in waters of the Western Tropical North Atlantic.
When icebergs fracture from ice sheets they often become trapped in a dense icy aggregation called mélange that fringes the coastlines of Greenland and parts of Antarctica. This melange controls the annual cycle of ice sheet mass loss through iceberg fracture at many glaciers and also the rate at which icebergs enter into the open ocean. Once in the open ocean, icebergs can influence ocean circulation through the input of fresh meltwater and may also cause hazardous conditions in Arctic shipping lanes.
Ice sheets have gone through periods of rapid melting, causing sea level to rise many times faster than the current rate of rise. Some of these rapid melting events have occurred during periods when ocean and atmospheric temperatures were at or just above modern temperatures. It is thought that there are instabilities intrinsic in the dynamics of ice sheet flow and melting that may cause such rapid sea level rise events, even without changing climate.
Nonlinear dispersive wave groups or packets occur in a wide range of natural systems, exhibiting complex behaviors especially in focal zones where there is rapid wave energy concentration and possible wave breaking. In the presence of dispersion, pure plane waves of different wavelengths and directions traveling within a medium have different propagation velocities. Important classes of geophysical wave systems include surface gravity waves, oceanic and atmospheric internal waves, and seismic waves.
The recently completed resource assessment for ocean current energy (Haas et al. 2013) utilized fairly simplistic analytical methods to estimate the extractable energy from the Gulf Stream System as well as to analyze the relative impacts of large scale energy extraction. This level of analysis can be considered to be accurate to an order of magnitude and only provides an idea on the overall trends of the impacts of extraction. Much higher resolution modeling is required to accurately determine the overall impacts of extraction for both localized and far field effects.
The student will work jointly between the labs of Drs. Frank Stewart (Biological Sciences) and Kostas Konstantinidis (Biological Sciences, Civil and Environmental Engineering) to characterize a globally important marine bacterial group (SAR11). A collaboration between these labs recently described how SAR11, the world’s most abundant organismal group, has adapted to the unique chemical and physical environment of anoxic oxygen minimum zones (OMZs). This work (Tsementzi et al.
The effects of climate change on the coastal ocean include a decrease in riverine inputs and increase in salinity in estuaries with impacts on primary production, macrofauna, and sediment biogeochemistry that are poorly understood. One clear effect of the increase in salinity associated with the decrease in riverine discharge, however, is the enhanced coagulation of inorganic material further upriver. Flocculation of particulate material upriver will enhance its flux to the sediment and simultaneously decrease the outflux of particulate material to the continental shelf.
The urbanization of the coast is generating significant environmental issues, including increasing nutrient runoff that promotes eutrophication and hypoxic conditions in estuaries. At the same time, the excessive input of nutrients is also responsible for an increase acidification of coastal waters, as denitrification in sediments typically generates acidity.
CO2 emission will continue exaggerating, as fossil fuels will most likely remain the major source of energy in next couple decades. The increased carbon in the atmosphere moves into marine ecosystems, making the world’s oceans more acidic. The rate of ocean acidification (OA) today is faster than any time in the past 300 million years.
