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.
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.
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.
