Passage:
For decades, marine geologists hypothesized that cold-water carbonate mounds—large undersea structures built from the skeletal debris of cold-water corals—formed primarily through the upward seepage of hydrocarbon-rich fluids from the seabed, which provided chemical energy for microbial mats that fueled coral larvae settlement. However, recent oceanographic surveys across the North Atlantic margin present a different picture. Researchers analyzed sediment cores from several prominent mound complexes and discovered that while deep subsurface methane leaks were occasionally present, they did not coincide temporally with the key initiation phases of mound development. Instead, high-resolution acoustic profiling and isotopic analysis revealed that mound growth spiked during periods of heightened bottom-current activity and enhanced surface water productivity. The authors of the recent study assert that cold-water carbonate mound formation is governed predominantly by hydrodynamic delivery of organic nutrients from surface waters rather than by benthic hydrocarbon seepage.
Which of the following, if true, would most weaken the authors' assertion regarding the primary cause of cold-water carbonate mound formation?
- Radiocarbon dating of coral skeletons within the earliest foundational layers of several major Atlantic mounds shows that initial reef colonization occurred exclusively during geological intervals when seabed hydrocarbon seepage reached peak intensity.Cevap
- BSediment samples taken from oceanic regions with weak bottom currents contain significantly lower concentrations of cold-water coral fragments than samples taken from high-velocity current channels.
- CCommercial deep-sea fishing trawlers operating in the North Atlantic have damaged up to fifty percent of shallow coral reefs, drastically reducing organic nutrient transport to deep-sea benthic ecosystems.
- DMounds located in ocean regions with high surface water productivity host more diverse benthic organisms than mounds located in nutrient-poor surface waters.
- EEarlier marine geologists lacked the high-resolution acoustic profiling tools required to detect deep subsurface methane leaks in sediment layers.