The ecological and geological response to the introduction of a nearshore reef in southern Lake Michigan

Schmidt, Amber Rose

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https://hdl.handle.net/2142/127292 Copy

Description

Title

The ecological and geological response to the introduction of a nearshore reef in southern Lake Michigan

Author(s)

Schmidt, Amber Rose

Issue Date

2024-12-12

Director of Research (if dissertation) or Advisor (if thesis)

Czesny, Sergiusz J

Committee Member(s)

• Glandon, Hillary L
• Suski, Cory D
• Phillips, Andrew C
• Parkos III, Joseph J

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Lake Michigan
• Artificial Reef
• Invertebrates
• Round Goby
• Ecology
• Geology

Abstract

The Great Lakes are susceptible to costal erosion through weather events, high water levels, and wave action. These receding coasts create challenges for both cities and natural areas across the Great Lakes. Historic solutions to this problem have been temporary and provide no long-term solutions. The Rubble Ridges is an artificial reef system designed to be a dynamic, natural solution that mitigates erosion and repairs the natural shoreline. The Rubble Ridges reef site was constructed in the summer of 2021 to prevent sediment erosion near Illinois Beach State Park in southwestern Lake Michigan. The intent of this study is to determine if a newly constructed nearshore artificial reef impacts the local sediment characteristics at the reef, and if these changes in sediment may influence the utilization of the reef by the benthic community. Benthic cores, round goby (Neogobius melanostomus) stomachs, and sediment cores were collected from the reef site and control site (4.8km south) while scrapes of biota attached to the reef structures and scrapes from Hester-Dendy samplers were collected from the reef site only. Changes to the ecosystem at the reef site included an increase in the abundance and diversity of the aquatic community, compared to the control site, over the two-year study. The top invertebrate taxa influencing these trends include Chydoridae, Cyclopoida, Dreissena bugensis, Pelecypoda, Gammaridae, Harpacticoida, larval Chironomidae, pupal Chironomidae, Nematoda, and Oligochaeta. The round goby stomach content analysis showed that the presence of Dreissena bugensis was the key to distinguishing between the diets of fish living within the reef structure from those living in the area surrounding the reef. Sediment grain size at the reef site became coarser and more heterogeneous, compared to the sediment grain size at the control site, over the two-year study. The reef site experienced scour and lag deposit during the two-year study period, which indicates the energy in the system was being redirected by the reef. This study showed that round goby were attracted to nearshore structures and supports previous studies on the inshore/offshore migration pattern of round goby in Lake Michigan. This study also showed that invertebrates are more likely to live on the reef structure than in the sediment, and that the addition of a nearshore structure increases invertebrate community density, biomass density, and taxa richness.

Graduation Semester

2024-12

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/127292

Copyright and License Information

Copyright 2024 Amber Schmidt

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