Warum Sauerstoff im Meer fehlt
"Im Meer gibt es immer mehr Stellen, in denen es kaum noch Sauerstoff gibt: sogenannte "Todeszonen". Wir erklären euch, warum das ein Problem ist."
NOAA, partners to report on 2020 Gulf of Mexico ‘dead zone’ monitoring cruise
NOAA and its partners will report on their recent research cruise to measure the extent of the hypoxic or “dead zone” in the Gulf of Mexico during a media teleconference on Tue., Aug. 4 at 11:00 a.m. EDT.
In June, NOAA scientists forecasted this summer’s dead zone – an area of low to no oxygen that can kill fish and other marine life – to be approximately 6,700 square miles. That is larger than the long-term average measured size of 5,387 square miles, but substantially less than the record of 8,776 square miles set in 2017.
Slightly smaller-than-average 2020 ‘dead zone’ predicted for Chesapeake Bay
"Researchers from the University of Michigan, the Chesapeake Bay Program and the University of Maryland Center for Environmental Science are forecasting a slightly smaller-than-average Chesapeake Bay “dead zone” this year, due to reduced rainfall and less nutrient-rich runoff flowing into the bay from the watershed this spring. [...]"
Source: University of Michigan
Larger-than-average ‘dead zone’ expected for Gulf of Mexico
"NOAA scientists are forecasting this summer’s Gulf of Mexico hypoxic area or “dead zone” – an area of low to no oxygen that can kill fish and other marine life – to be approximately 6,700 square miles, larger than the long-term average measured size of 5,387 square miles but substantially less than the record of 8,776 square miles set in 2017. The annual prediction is based on U.S. Geological Survey river-flow and nutrient data. [...]"
Chesapeake Bay water quality declines by four percentage points
"An estimated 38% of the Chesapeake Bay and its tidal tributaries met clean water standards for clarity, oxygen and algae growth between 2016 and 2018. This score is lower than the record high 42% from the previous reporting period, but is still the fifth highest estimate of water quality standards attainment since 1985. This four percentage point decrease is due in large part to a decline in dissolved oxygen in the open waters of the Bay, those areas beyond the shoreline and shallows. Dissolved oxygen is necessary for the survival of the Bay’s aquatic species, and is a factor in the annual dead zone. [...]"
Uncovering diversity and metabolic spectrum of animals in dead zone sediments
"Ocean deoxygenation driven by global warming and eutrophication is a primary concern for marine life. Resistant animals may be present in dead zone sediments, however there is lack of information on their diversity and metabolism. Here we combined geochemistry, microscopy, and RNA-seq for estimating taxonomy and functionality of micrometazoans along an oxygen gradient in the largest dead zone in the world. [...]"
Source: Communications Biology
Authors: Elias Broman et al.
Fishing trawlers could harm water quality by disrupting seafloor microbes
Is there a technological solution to aquatic dead zones?
"Could pumping oxygen-rich surface water into the depths of lakes, estuaries, and coastal ocean waters help ameliorate dangerous dead zones? New work says yes, although they caution that further research would be needed to understand any possible side effects before implementing such an approach. [...]"
Source: Science Daily
Understanding Long Island Sound's 'dead zones'
"For the past 25 years, the Environmental Protection Agency and the Connecticut Department of Energy and Environmental Protection have been diligently collecting water samples each month in Long Island Sound (LIS). Recently, the data have been compiled and analyzed, by UConn associate professors of Marine Science Penny Vlahos and Michael Whitney, and other team members, who have begun the task of digging into the data to better understand the biogeochemistry of the Sound. Part of the analysis, called "Nitrogen Budgets for LIS," has been published in the journal Estuarine, Coastal and Shelf Science. [...]"
Anaerobic Activity Is a Big Contributor in Marine “Dead Zones”
Climate models that do not account for anaerobic microbial activity may underestimate future expansion of oxygen-depleted waters.
"Certain parts of Earth’s oceans are so oxygen depleted that they can hardly sustain life. Climate models predict that these “dead zones” will expand as global warming progresses, affecting ecosystems, fisheries, and the climate itself. Now Lengger et al. provide new evidence that such predictions do not adequately account for the activity of anaerobic microbes that consume inorganic carbon within dead zones. [...]"