Summer 2023 Hypoxia Monitoring

Hypoxia Monitoring Overview

The 2023 sampling schedule included routine water quality surveys as well as summer-only hypoxia surveys.

Routine water quality surveys are conducted year-round, including during the summer months.  During these surveys water samples are collected for from 17 stations and analyzed for nutrients and other water quality parameters.  In addition, phytoplankton and zooplankton samples are collected from 6 stations in the Sound.

Hypoxia surveys are conducted during the months of June through September at an additional 30 stations.  During hypoxia surveys, stations are sampled for dissolved oxygen to get a more accurate understanding of the extent of summer hypoxia conditions in Long Island Sound bottom waters.

DEEP's Long Island Sound Water Quality Monitoring Program utilizes data from both surveys to  monitor the extent of low dissolved oxygen in Long Island Sound bottom waters, or 'summertime hypoxia'.  Hypoxia condition maps were posted as soon as possible after each survey.   Biweekly newsletters, summarizing the results of each survey, are also distributed to interested parties.

2023 Monitoring Results

Select a sampling date below to view the progression of hypoxia in the western Sound throughout the summer of 2023.

Winter 2023

• Winter Summary (Vol. 6, Issue 1)

Spring 2023

• Spring Summary (Vol. 6, Issue 2)

June 2023

• Water Quality Survey (WQJUN23) Summary (Vol. 6, Issue 3)
• WQJUN23 Hypoxia Map (May 31- June 2, 2023)
• Hypoxia Survey (HYJUN23) Summary (Vol. 6, Issue 4)
• HYJUN23 Hypoxia Map (June 23, 2023)

• Water Quality Survey (WQJUL23) Summary (Vol. 6, Issue 5)
• WQJUL23 Hypoxia Map (July 5-10, 2023)
• Hypoxia Survey (HYJUL23) Summary (Vol. 6, Issue 6)
• HYJUL23 Hypoxia Map (July 17-19, 2023)  

• Water Quality (WQAUG23) Survey Summary (Vol. 6, Issue 7)
• WQAUG23 Survey Hypoxia Map (July 31-August 3, 2023) 
• Hypoxia Survey (HYAUG23) Summary (Vol. 6, Issue 8) 
• HYAUG23 Survey Hypoxia Map (August 14-16, 2023)

• Water Quality Survey (WQSEP23) Summary (Vol. 6, Issue 9)
• WQSEP23 Hypoxia Map  (August 29, September 6-7, 2023) 

LIS Hypoxia Monitoring Distribution List

Interested in receiving future biweekly survey summary newsletters?  Email Katie O'Brien-Clayton at Katie.Obrien-Clayton@ct.gov to be added to the distribution list.

Long Island Sound Water Quality Monitoring Program Maps

Content last updated December 3, 2024