Ohio Miami University reservoir water chemistry and foodweb data 1992-2010

This research examines how landscapes (watersheds) and food webs interact to regulate
ecosystems, focusing on reservoirs of the Midwest USA. This research is collaborative with two
other Miami faculty, María González and Bill Renwick, and many students. We are
examining how watersheds and omnivorous fish influence lakes along a gradient of watershed land
use, ranging from mostly forested watersheds to those that are nearly entirely agricultural.
Data provided by Mike/Maria include dissolved nutrients, suspended sediments, DOC,
temperature/oxygen profiles, and water clarity from 1992-2010 with frequency and duration of
sampling varying among reservoirs. sampling was typically conducted at two sites: (a) a shallow
‘inflow’ cite at the upstream area of a reservoir where the inflowing lotic system
is transitioning to a more lentic one, and a deeper ‘outflow’ site just upstream of
the dam. Most samples for water chemistry analysis were collected with integrated samplers from
the euphotic zone or epilimnion (which usually are the same for these lakes - Vanni comment).
For most of our sampling (all the Acton sampling and other sampling done by MU), we measured the
depth of the eophotic zone using a light meter (z_eup = depth where light = 1% of surface
light). When the ODW collected samples, they did not have a light meter so we used the
epilimnopn, which we defined as any depth where oxygen was > 2 mg/L. As I mentioned, because
our lakes are pretty productive, oxygen concentrations are usually driven by phytoplankton
production so the eiphotic and epilimnetic depths are the same. For some things, we take
replicate integrated samples, and we run duplicates on both of those, for a total of 4 values.
For example, for chlorophyll we take two samples (two bottles) and run duplicates on both and we
label the samples 1a,1b,2a,2b. ….the data we sent you are always means of those
values….’.