PHOSPHORUS EQUILIBRIUM AS INFUENCED BY MICROBIAL COMMUNITITES WITHIN SEDIMENTS

Terrestrial environments provide important nutrients, such as phosphorus, to the freshwater tributaries that surround them. Despite current reduction efforts set out by agencies, there is still sufficient phosphorus loading discharged to freshwater systems inducing anthropogenically accelerated eutrophication. One method of phosphorus loading generates from nonpoint sources, which are diffuse and include agriculture. In Lake Erie, phosphorus loading from nonpoint sources account for 88 to 93 % of inputs to the lake. In small tributaries, phosphorus loading from agricultural fields are partially altered by a sediment buffering mechanism that governs phosphorus sorption. Where phosphorus buffering capacity had, historically, been strictly related to sediment sorption and desorption, current studies prove that microbial communities play an important role in this mechanism. Despite their undeniable importance, sediment microbial communities are severely under characterised and typical laboratory adsorption experiments do not favor biotic processes. During batch adsorption studies, sediments are disrupted via sampling, transportation, homogenization, and are subjected to light exclusion which may suppress biotic activity. Additionally, the mechanism of shaking utilized in these experiments disrupts biofilms, modifies redox structure, and increases surface area of mineral phases in a way that is no longer representative of the consolidated interface that is present in-situ. This research explores the use of mesocosms (core samples to be manipulated by a flow-through design in such a way as to preserve the sediment-water interface disturbing the microbial community as little as possible. The adsorption information gleaned from this type of experiment is then be combined with broader molecular approaches that address microbial function in the sediments at the interface via RNA-sequencing, such as metagenomics. 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: