Which of the following are true about Nansen bottles?

Nansen bottles are specialized tools used in oceanography for collecting water samples from various depths in the ocean. One of their primary functions is to record water temperature at those depths. When the Nansen bottle is deployed, it is equipped with a thermometer that measures the temperature of the water surrounding the bottle at the moment of closure. This allows researchers to obtain reliable data about thermal gradients in the ocean, which can be crucial for studying ocean circulation and marine ecosystems.

In contrast, the other options refer to functionalities that are not directly associated with the Nansen bottle. For instance, Nansen bottles do not sample bottom sediments; that function is typically performed by devices specifically designed for sediment collection. Testing for minute marine life usually involves different types of sampling equipment, like nets or water samplers with filters. While Nansen bottles can be handled from the surface, they are not generally used by hand; instead, they are typically deployed from research vessels using a winch or a similar apparatus to reach the desired depth.