13: Coastal Oceanography - Geosciences
After reading this chapter you should:
- recognize the various zones of a beach
- understand how the relationship between swash and backwash determines the composition of a beach
- understand the concept of longshore transport
- know the different erosional and depositional structures created by longshore transport
- understand the issues associated with different forms of hard stabilization: groins, jetties etc.
- know what an estuary is
- know the four types of geological estuaries, and how they form
- know the four types of estuaries based on salinity and mixing patterns
For most people, their image of the coast is the place where the land meets the sea, most likely in the form of a beach. But it is more than just the narrow strip along the water line; technically the term “coast” refers to the range of land over which the ocean has an effect on climate, foliage, and other environmental processes. This range may extend for tens of kilometers inland from the water’s edge. Furthermore, what we recognize as the coast today, may not have been a coastal area in the past, as sea level has varied from about 6 m above to 125 m below its current height over the past two million years.
This chapter begins with the features of coastal regions, the processes that shape the coastline, and how humans try to control these processes. Following that, we will examine the different types of estuaries that are found in coastal areas.
Introduction to Oceanography
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“At Texas A&M Oceanography department, you will never take a class where the professor isn’t incredibly passionate about what they are teaching. It’s infectious.” – Charlotte Miller '20
“Texas A&M OCNG has nourished my passion in environmental sciences” – Dr. Lei Hu '12 (Ph.D.)
Faculty in the Department of Oceanography and KAMU-FM have created an oceanic science podcast, On the Ocean, that shares important facts about the ocean, marine creatures, and oceanographic research.
KAMU-FM airs On the Ocean Tuesdays at 8:30 AM CT. Podcasts, text, and links will be uploaded on this site shortly after.
13: Coastal Oceanography - Geosciences
About Marine Geosciences, Oceanography and Informatics
Geosciences, Oceanography, and Informatics (GOI) section undertakes training in the subjects of physical and geological oceanography, remote sensing, and GIS. It carries out research in the same areas and offers consultancy services in the areas of physical, chemical, and geological oceanography and use of satellite information including remote sensing and GIS in the ocean and coastal studies. In addition, the section ventures into applied areas including issues related to coastal processes, beach erosion, shoreline change, climate change, etc. where advice is provided to the government and the public in general. The section also works in support of the activities of other sections of the Institute and the University of Dar es Salaam.
Staff List in Geosciences, Oceanography and Informatics (GOI)
Associate Professor and Head of Section
N. M. Nyandwi, BSc (Geol) (Dar), MSc (Wales), Dr. rer. nat. (Bremen)
D. C. P. Masalu, BSc (Dar), BSc (AICS), MSc, DSc (Tokyo)
C. A. Muhando, BSc (Dar) PGD (Fisheries Biology) (Bergen), MSc (Brussels), PhD (Dar)
***Y. W. Shaghude, BSc (Dar), Adv, Dip Marine Affairs (Dalhousie), MSc (Southampton), PhD (Stockholm)
Mead Allison joined the Institute for Geophysics as a senior research scientist in August 2007. Allison’s research focuses on coastal geological oceanography, including both the modern and paleo environments.
“Most of my work is around the transition where large rivers impact the ocean, the river-dominated continental margin,” Allison said. “These are areas where there are the largest and most rapid accumulations of continentally derived sediments. This is interesting because you have a way to look at modern systems of sedimentary strata formation that can inform us about ancient fluviodeltaic and marine analogs.”
These areas are potentially extremely valuable paleoclimate records as well. They are challenging because they are so dynamic in location and how they are shaped by marine processes, but they could provide a higher resolution record compared to locations farther offshore. Allison’s recent research has focused on the Mississippi Delta region.
Comparison of distribution of river bottom dunes under low (left) and high (right) discharge scenarios. Image based on multibeam bathymetry data from the lower Mississippi River at Audobon Park, New Orleans. Courtesy of Mead Allison and JSG doctoral student Jeffrey Nittrouer.
“You have this thick, rapidly accumulating sediment adjacent to rivers that provides a high-resolution climate record that includes both organic and inorganic materials,” Allison said. “The nice thing is, compared to tree rings or ice cores, this record is specific to conditions on the adjacent continent. If you look at the Mississippi, you are studying two-thirds of the country. It’s less sensitive to local climatic changes and more integrative of factors that are continental in scale.”
The record from the historical period in the Mississippi has revealed surprisingly detailed information, including the effects of dam construction, institution of soil conservation, clearance for agriculture, and other human activities.