10/10/11
Frank Muller-Karger, PhD
College of Marine Science, University of South Florida, St. Petersburg, FL.
The CARIACO program conducts monthly oceanographic cruises to the Cariaco Basin (10°30’N, 64°40’W, SE Caribbean Sea) since November 1995. This basin is connected with the Caribbean Sea in the upper 140 m and is well ventilated above this sill depth, but waters below ~250 m are anoxic. The time-series objective is to understand the relationship between hydrography, community composition, primary production, microbial activity, terrigenous inputs, sediment fluxes, and element cycling in the water column, and how changes in these processes are preserved in seafloor sediments. The observations show major changes have occurred in the oceanography of the Basin since the mid-2000’s, with primary productivity falling by 20-30% from >500 gC m-2 y-1 in the late 1990’s. We discuss trends in several parameters, including a sharp decrease in sardines in the region. An ecosystem shift has resulted from a decrease in the Trade Wind intensity and weaker coastal upwelling.
Frank E. Muller-Karger is a biological oceanographer (Professor) at the College of Marine Science, University of South Florida, where he directs the Institute for Marine Remote Sensing. He conducts research on marine primary production using satellite remote sensing, large data sets, networking, and high-speed computing. This research helps in the location and monitoring of large-scale phenomena, understanding climate control and climate change, and in the interpretation of numerical models of the ocean. He assess the importance of continental margins, including areas of upwelling, river discharge, and coral reefs in the global carbon budget, using satellites that measure ocean color and sea surface temperature.
I'm looking forward to answers to the following questions in today's presentation.
ReplyDelete1) It will be interesting to know how the this program, Carbon Retention in a Colored Ocean, (CARIACO) provides insight to the relationship between surface primary production, physical forcing variables like winds, and the settling flux of particles in the a specific geographical location.
2)Periodically, oceanographic cruise are conducted to collect hydrographic, nutrient and carbon concentration throughout the entire water column. How are these information used to examine chemical and microbial processes.
This talk was absolutely fascinating. The Cariaco Basin is a big, deep hole where there is a geological fault, and this limits mixing of water. This makes the conditions in the deep anoxic, which in turn serves to preserve the sediment and stabilize it thanks to lack of sea animals burrowing, eating, living, etc.
ReplyDeleteThe sediment cores are a record of paleo-history going back 600,000 years!
I found a lot of information in Dr. Muller-Karger's lecture to relate to my current studies. When he talks about substrates falling from the ocean surface, and the microorganisms present at depths, it is an example of Terminal Electron Acceptor Process (TEAP) zones. Aerobic bacteria are dominant at the shallower depths, where sulfate reducing bacteria takeover at anoxic environments.
ReplyDeleteI think it is interesting how most of his research can backup the disappearance of the sardine population in Cariaco. I also find it unfortunate that fishing data is not accurately kept so that the data collected could be used to formulate an hypothesis as to the disappearance of the sardine species in the area.