US Long-Term Ecological Research Network
1. When to Sample: To determine the sampling dates, follow the same schedule as done in past years. It is best to make out the calendar for the whole year and sign-out a vehicle and boat far in advance. Check the past year’s sampling calendar for agreement in dates.
a.     The sampling schedule is made by working back from the Monday closest to September 1. 
1.     The September 1st week is considered a 'profile sampling' with more extensive nutrient and chlorophyll sampling (refer to the field sheets from the same sampling week of the past year for sampling depths and parameters). 
2.     Working back from the September 1st sampling week, a sampling week starts every other Monday back to when the lakes open up in March. 
3.     Working forward from the September 1st sampling week, the lakes are sampled every 4 weeks until the end of November (find the next and subsequent sampling weeks by counting 4 weeks ahead starting from the Monday closest to September 1st)
4.     'Profile' or extensive and 'Non-Profile' or less extensive sampling weeks alternate during the every 2 week sampling (refer to past years field sheets).
5.     One sampling set is done through the ice and another if weather permits. These sampling sets are spread as far apart in time as is safe. The first sampling is done shortly after the ice forms when it is safe to work on and the second sampling is done shortly before the ice becomes unsafe to work on. Starting in mid-to-late February, it is important to be ready to sample at a moments notice and to start the sampling week at the beginning of a warm spell. 
2.   What to Sample for: Because sampling consistency is a goal of the project, the easiest way of figuring out what to sample for is by looking at the past year’s field sheets (find the corresponding sampling dates). Following are clarifying points for frequently misunderstood aspects of weekly sampling:
a.     Chlorophyll depth profiles to be analyzed fluorometrically are done during 'profile' samplings when the lakes are stratified. These are generally done every 2 meters starting at 0 meters and ending at 12 meters. On Fish Lake, 1-meter intervals are sampled for chlorophyll in the metalimnion (to try to detect a metalimnetic bloom)
b.       0-2 meter integrated chlorophyll samples are taken from each of the six lakes during every sampling period and are taken in duplicate for both spectrophotometric and fluorometric analysis.
c.        Zebra mussel veliger sampling is done monthly in the summer during non-profile sampling (see zebra mussel folder).


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