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.
A large fraction of ocean variability on interannual and longer timescales is energized by random atmospheric weather, also referred to as climate "noise". Although the noise is random in time, spatially the atmospheric noise exhibits recurrent patterns, some of which are more efficient in triggering positive feedbacks between the ocean-atmosphere system or more generally amplifying the response of the ocean system. Noise patterns such as these, can trigger resonance in the climate system.
The sustainability of human civilization and its evolving lifestyle depends fundamentally on a sustainable food and energy supply. This can largely be linked to the availability of reactive nitrogen (Nr), phosphorus (P) and trace-element nutrient availability for natural and managed ecosystems. Nr, P and Fe are known to stimulate productivity while other elements, like Cu and Mn, can be toxic for ecosystems. Nr is also a critical link for the carbon cycle, and directly/indirectly impacts climate and human/ecosystem health.
The exponential growth of human populations in the Mekong-South China Sea (SCS) system, the eutrophication of estuarine and coastal waters by excess nutrients transported by the Mekong River, and the rapid sinking of the Mekong Delta are fundamentally changing the biological productivity and biodiversity of the system, with uncertain implications these aquatic resources. In the near future, larger forcings will alter the linkages between the Mekong system and the SCS basin.
Deep subsurface methane hydrate-bearing sediments contain microbial communities that are distinct from shallow marine sediments and hydrate-free environments. DNA evidence suggests that novel bacterial phyla (e.g. Atribacteria) are highly enriched in methane hydrate-bearing sediments. Recent genome assemblies by the Glass group at Georgia Tech are providing insights into the metabolic potential of samples drilled from gas hydrate stability zone 70 mbsf below Hydrate Ridge (IODP Leg 204).
Geochemical time series from remote Pacific atolls have provided long records of climate variability that extend into the pre-industrial era. Recent studies document a wide range of geochemical variability in corals growing on the same reef, ostensibly of the same genus. Deciphering which fraction of coral geochemistry variations are driven by changes in physical environment versus physiological differences between corals is key to constructing more robust records of past climate variability.
The project aims at further testing a new approach, the maximum entropy production (MEP) model of surface heat fluxes (Wang et al, 2014), for modeling and monitoring air-sea exchange of water and heat air-sea water and heat.
