Question: what is the term for the colder denser water below the thermocline in a fresh water lake
[{'answer': 'hypolimnion', 'provenance': [{'wikipedia_id': '619980', 'title': 'Thermocline', 'start_paragraph_id': 9, 'start_character': 323, 'end_paragraph_id': 9, 'end_character': 334, 'bleu_score': 1.0, 'section': 'Section::::Other water bodies.\n'}]}, {'provenance': [{'wikipedia_id': '619980', 'title': 'Thermocline', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 508, 'bleu_score': 0.9768747032089851, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11133015816867873156}, 'section': 'Section::::Other water bodies.\n'}]}]