Zgodnie z programem Szczecin Marginal Seas Webinars w semestrze wiosennym 2021/2022, kolejny webinar jest planowany na 24 marca 2022, 2:00 pm (CET).

Podczas spotkania online zostanie przedstawiony wykład: "Fluxes and fates of Asian major river derived sediments to the sea"

prezentowany przez Prof. Dr. Paul Liu,

Dept. of Marine, Earth, & Atmospheric Sciences, North Carolina State University, USA

Abstract

Recent field studies off the Yellow, Yangtze, Pearl, Mekong, Irrawaddy, and Ganges show less than 50% of these river-derived sediments has been deposited near the river mouth, and rest of them discharges into their adjacent seas. Among those being discharging into the ocean, nearly half of them has been found to be longshore-transported several hundred kilometers from the river mouth. For example, besides the large proximal delta plains near their river mouths, the Yangtze River sediment has been transported ~800 km into the Taiwan Strait, and Yellow River sediment has deposited more than 700 km into the south Yellow Sea. And both the systems have developed a 40-m thick distal mud depocenter. Parallel to the shore, the Mekong-derived sediment has extended >250 km southwestward to the tip of the Ca Mau Peninsula, forming a distal mud depocenter up to 22 m thick, and extending into the Gulf of Thailand. Most recent surveys off the Irrawaddy River Delta indicate, not like other Asian river system, this river disperses its sediments into both east and west sides in the Andaman Sea and Bay of Bengal under different monsoon driving forces. The Ganges-Brahmaputra is the only major Asian river currently delivers a large amount of sediments directly to the deep sea floor via its shelf-cut canyon. This is also true in other large river systems, like the Amazon, Mississippi, and Nile rivers. There is very little or few percent of the total sediment discharge has been found to be across-shelf transported into the deep ocean, except for a few shelves with canyon systems, such as Congo and Ganges. The large distance longshore transport and distribution of the river derived sediments and geochemical elements have some significant bio-geo-chemical impacts on the marine environments. Our most-recent studies of the world major river systems show that, in the past 50 years, sediments from most of world rivers have sharply decreased 80-90% due to the increased human activities (like building dams, overusing water, or sand mining) and climatic changes. Many of those river deltas have been experiencing severe coastal erosions, like the Chao Phraya, Colorado, Indus, Mekong, Mississippi, Nile, Red, and Yellow rivers, etc.  Most of these deltas have turned from constructive growing mode to destructive declining mode, for example, the Mekong Delta is now losing ~30 m of its delta per year.

Więcej informacji: https://www.meas.ncsu.edu/sealevel/publications.php

The meeting room will be open from 1:30 pm (CET), but the seminar will begin at 2:00 pm (CET).
To join the meeting please use the link:
https://teams.microsoft.com/l/meetup-join/19%3a0ee21c3b364e4709810bc45b7fbb4284%40thread.tacv2/1646828404330?context=%7b%22Tid%22%3a%22af892dd6-4563-4455-9c05-a398a43f2362%22%2c%22Oid%22%3a%221e9df312-5fc1-4e40-bc0d-ab7f66ee7bd8%22%7d

or use the code: 2sc5rph