Defense Date

12-1-2020

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Jose Lopez, Ph.D.

Second Advisor

Hidetoshi Urakawa, Ph.D.

Third Advisor

Robert Smith, Ph.D.

Abstract

Symbionts within marine sponges are actively participating in the biogeochemical cycles. Among them, the role of symbiont microbes in the sulfur cycle remains a mystery. This study measured the abundance of microbes within the genus Cinachyrella before and after exposure to hydrogen sulfide. A four-part study was conducted: a) five-hour drop experiments, b) vertical distribution experiments, c) five-hour uptake experiments, and d) long-term exposure experiments. The five-hour drop experiment utilized a microsensor to measure sulfide levels, which was lowered 1.0 mm every thirty minutes for a total of 5 hours. Three trials were performed, each with one sponge and a control with no sponge. The vertical distribution experiments measured hydrogen sulfide levels throughout 9.0 mm. A five-hour uptake experiment measured hydrogen sulfide over five hours without the use of microsensors. The bacterial composition was detailed during long-term exposure experiments, where three sponges were exposed to 60 μmol/L for several weeks. Tissue samples collected from the long-term exposure experiment underwent microbial DNA extractions and high-throughput sequencing. Hydrogen sulfide concentrations from the five-hour drop, vertical-distribution, and five-hour experiments underwent various generalized additive models and generalized linear models. A significant relationship between time (depth for the vertical-distribution) and hydrogen sulfide concentration (p-valueDraconibacterium, family Rhodobacteraceae, and genus Halodesulfovibrio within sponges. These data suggest that Cinachyrella spp. can filter and process hydrogen sulfide from the water column with help from its microbiome.

Share

COinS