Where on Earth...? MISR Mystery Image Quiz #19: Black Sea

Other formats available at JPL.

This natural-color image of the Black Sea from the Multi-angle Imaging SpectroRadiometer (MISR) represents an area of about 375 kilometers x 407 kilometers, and was captured by the instrument's vertical-viewing (nadir) camera in May, 2002. Answers to the questions are provided.

1. Three of these statements about the large water body are false. Which one is true?

   1. The deepest portion of the water body is less than 2000 meters deep.
   2. The shallow waters of the northwest section of the water body are less saline than in deeper waters.
   3. A rich biological community of worms and crustaceans thrive in the mud below 180 meters depth.
   4. Algae and plankton form a vast and productive underwater "meadow" in the relatively shallow northern waters.

   • Answer: B is true
     The Black Sea is the largest anoxic (oxygen poor) sea in the world. The deepest part of the Sea is over 2 kilometers, but there is very little oxygen below the top few hundred meters. Replenishment of the bottom waters of sea with new sea water from the Mediterranean is slow, and there is very little circulation between the relatively fresh shallow waters and the saltier, oxygen poor waters at great depths. The bacteria in the bottom waters quickly consume the available oxygen and the Sea is virtually dead below the top 200 meters. Despite this situation, its surface waters have supported a rich and diverse marine life. The relatively shallow north-western part of the Black Sea was virtually covered with "underwater meadows" known as Zernov's Phyllophora fields. The rivers which drain to the Sea provided the nutrients essential for marine plants and algae, until over-fertilization from agriculture and industry in the 1970s and 1980s caused the Phyllophora ecosystem to suffer a catastrophic collapse.

   
   

2. Three of these statements about the large water body are true. Which one is false?

   1. The pale blue swirls of color in these waters indicate calcareous phytoplankton called coccolithophores.
   2. Since the 1960s, coccolithophores have become more abundant, and diatoms (another type of phytoplankton) have decreased.
   3. Early seafarers used the prevailing clockwise circulation of the currents to navigate these waters.
   4. Archaeological relics discovered under 100 meters of water indicate that the coastline was lower several thousand years ago than today.

   • Answer: C is false
     One group of phytoplankton that are identifiable from space are calcareous phytoplankton called coccolithophores; and judging by the milky turquoise color of the swirls, it is probable that coccolithophores were in bloom. The increased nitrogen content of river waters entering the Sea since the early 1970s is part of the reason for an increase in coccolithophores and a decrease in diatoms (siliceous plankton) since that time. The Black Sea current runs counterclockwise and was utilized by early navigators. The Sea is a rich source of archaeological relics, since many ancient wooden vessels are preserved in the oxygen-deprived waters. One archaeological site from which ships and relics were recovered is situated below 100 meters of water in an area that appears to have been a coastline several thousand years ago.

   
   

3. Three of these statements about human activities within the area are true. Which one is false?

   1. There have been more than 10 geological studies conducted to determine the petroleum potential of the region.
   2. More than 20 fish species once found in the large water body have become "commercially extinct" over the last 50 years.
   3. One country within the image area is reported to have a 99.7% literacy rate or better.
   4. Many of the navigable rivers are forced to close for up to one month during winter.

   • Answer: D is false
     An array of geological studies and surveys have been conducted to assess the oil and gas resources od the Black Sea. The traditional livelihood of fishing in the Sea has been suffering in recent years, with 21 of the 26 major species now considered "commercially extinct" due to over-fishing, pollution and invasive species. The literacy rate (the proportion of people aged 15 and over who can read and write) in both Romania and Ukraine is high, but the literacy rate for Ukraine is especially high at 99.7% for the year 2003. The region can become bitterly cold in winter, with temperatures recorded as low as -30 degrees Celsius. During the winters of 1928-1929, 1953-1954, 1941-1942, 1984-1985, many coastal areas were frozen for 45-60 days. Only the north-western part of the Black Sea ices over during such cold winters, but within this area ports and rivers can freeze for more than a month. Whilst important ports and navigable rivers are kept open by ice-breakers, rivers that are not broken up by ice-breakers may freeze for two months.

   
   

4. Three of these statements about the river whose delta, or mouth, appears along the lower left-hand edge are false. Which one is true?

   1. The freshwater inflow from this river to the large water body is approximately twice the amount of saltwater inflow to the large water body.
   2. The entire river delta falls under the jurisdiction of one country.
   3. Contaminated water from a mining disaster that occurred hundreds of kilometers upstream (in January 2000), took less than 30 days to reach the river mouth.
   4. Over the past 20 years, the discharge of nitrates and phosphates from this river have decreased compared with 1960s levels.

   • Answer: C is true
     About 60% of the total freshwater inflow to the Black Sea comes from the Danube River (about 200 km3/year), and the volume of saltwater flowing to the Black Sea through the Bosporus is estimated to be between 120 km3/year and 315 km3/year. Thus, the volume of inflow from the Danube is not twice the volume of the inflow from the Bosporus. Most of the Danube Delta falls under the jurisdiction of Romania, but a small northerly portion of the Delta falls under Ukrainian jurisdiction. When the Baia Mare mining disaster contaminated the Tizsa River on January 30, 2000, contaminated water was brought down the Tizsa and into the Danube, and the cyanide pollution from the tailings overflow was detected at the mouth of the Danube on February 25. The nutrient discharge from the Danube to the Black Sea has been relatively stable for phosphates, but nitrogen levels are about four times those observed in the 1960s.

   
   

5. A rare bird that can weigh more than 45 pounds is known to inhabit:

   1. a nature preserve situated along the wide river that flows from the top of the image nearest to the right.
   2. lands surrounding the shallow, mineral-rich, pink and green-colored lagoons that extend from the upper right-hand edge of the image.
   3. neither of these places.
   4. both of these places.

   • Answer: D
     The Great Bustard (Otis tarda) is the largest land bird in Ukraine. Adult Great Bustards can reach about 48 pounds. The Askania-Nova Biosphere Reserve along the Dnieper River provides habitat for the Great Bustard. There are also a number of Great Bustards found in the Sivash (or Syvash) area, where a series of shallow, mineral-rich lagoons connect the Black Sea with the Sea of Azov. The Western and Central Syvash lagoons appear here as the pink and green-colored water bodies in the upper right-hand corner.

   
   

6. Bonus question:

   • A sinuous river curves toward the large water body in the upper-central portion of the image. Near the mouth of this river, a small orange spot can be discerned along the right-hand bank, near a small city known by two names. Name the most likely cause for the orange color at that location.

   • Answer:
     The orange area referred to is situated along the eastern (right-hand) shore of the Bug River, about 20 kilometers south of the city of Mikolayiv (or Nikolaev). The most likely cause of the orange color is "red mud", which is waste from the bauxite refining process. The area is likely to be an artificial lake or other storage area used to accumulate slurry, and the waste probably comes from the large Mikolayiv Alumina Plant

   
   

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
Text acknowledgment: Jim Armstrong (Potter Valley, California) and Clare Averill (Raytheon / Jet Propulsion Laboratory).