What implied *type* of water environment was Spirit seeking, contrasted with Opportunity's focus?

Lake water environment within a basin.

While both rovers shared the overarching goal of finding past water, their immediate scientific directives implied searching for different manifestations of that water, dictated by their landing sites. Spirit was positioned in Gusev Crater, where orbital data suggested a history of flowing channels and a potential lakebed. Therefore, Spirit's implied search was for the remnants of a large, standing body of water, primarily focusing on sedimentary layering indicative of a former lake environment. Opportunity, conversely, was focused on hematite concretions (“blueberries”) in Meridiani Planum, suggesting a search for evidence related to groundwater activity or localized surface pooling and alteration processes rather than a vast ancient lake.