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Zorluk: ZorLogical Inferences

Phytoplankton produce dimethylsulfoniopropionate (DMSP), which marine bacteria convert into dimethyl sulfide (DMS), a volatile gas that helps seed clouds and reflect solar radiation. Some marine viruses lysogenize phytoplankton, delaying cell death during nutrient-rich periods but triggering rapid lysis under ultraviolet-B (UVB) stress. A research team hypothesized that increased UVB radiation, which typically damages phytoplankton, might paradoxically accelerate DMS-induced cloud cooling. They found that although UVB stress did induce widespread viral lysis, releasing a massive pulse of DMSP into the water column, it also severely depleted the populations of DMS-converting bacteria that rely on living host exudates. Which choice most logically completes the text?

  1. A
    the bacteria will begin utilizing the released DMSP directly as an energy source to survive the effects of UVB radiation.
  2. the surge in DMSP release caused by UVB-induced lysis will not necessarily translate into an increase in cloud-cooling DMS gas.Cevap
  3. C
    viral lysis of phytoplankton will cease entirely once the population of DMS-converting bacteria drops below a critical threshold.
  4. D
    the lysogenic phase of the marine viruses will become permanent during prolonged periods of high UVB exposure.

Cevap

the surge in DMSP release caused by UVB-induced lysis will not necessarily translate into an increase in cloud-cooling DMS gas.
The passage establishes that the conversion of DMSP to DMS depends on marine bacteria. While UVB stress increases the availability of DMSP by lysing phytoplankton, it simultaneously depletes the bacteria responsible for converting DMSP into DMS. Therefore, it can be logically inferred that the increase in DMSP will not lead to a corresponding increase in DMS or the resulting cloud cooling.

Adım Adım Çözüm

1
Identify the premises regarding the creation of DMS.
DMS requires DMSP (produced by phytoplankton) and DMS-converting bacteria to perform the conversion.
Understanding the baseline mechanism of DMS generation is crucial for determining how it is affected.
2
Analyze the impact of UVB stress.
UVB stress increases the precursor DMSP through viral lysis but severely depletes the population of the bacteria needed to convert it into DMS.
This highlights the conflict between the increased supply of raw material and the decreased capacity to process it.
3
Draw a logical inference based on the conflict.
Since the necessary bacterial converters are depleted, the excess DMSP cannot be converted into DMS, meaning DMS levels and cloud cooling are unlikely to rise.
This directly connects the premises to form a valid, non-speculative conclusion.

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