This field lesson was designed as a quick introduction to the invertebrate fauna of Eagle Cove that can be completed in one morning. The lesson is divided into two sections, the first one (Microhabitat Comparisons in the Field ) takes place at the site and the second one (Sandy Beach Meiofauna ) is back at the lab.  

Click here for a copy of the handout (major themes, discussion questions, and field species list) provided during the 2004 class field lesson.

I. Microhabitat Comparisons in the Field


Time Allotted: ~2 hours

The focus of the lesson is a comparison of fauna between crevices vs. non-crevices and between vertical wall vs. overhang microhabitats on the rocky promontory. These two comparisons provide the most easily visible contrasts among fauna in the field. The main themes to emphasize are (1) various protection and locomotion strategies of the organisms found in the microhabitats, with an emphasis on resistance to desiccation and heat stress and (2) the scale of movement possible for different organisms, and how this affects there ecological interactions (i.e. sessile sponges vs. slow-moving limpets vs. extremely mobile crabs).

Students should be split into pairs, with each pair recording presence or absence of species in one 20 cm x 20 cm quadrat in each microhabitat with the help of the modified field species list (copy also listed on handout).  For the crevice/non-crevice comparison, students should  place the quadrat over a random crevice, and then take one small step directly outside the crevice at the same tidal height to place a second quadrat. For the vertical wall/overhang comparisons, students should compare two spots, one on an overhang and one completely exposed on the vertical wall, at roughly the same tidal height.

Consult the handout for topics to discuss before leaving the site, and be sure to collect core samples of sand for the meiofauna exercise (see below).

II. Sandy Beach Meiofauna


Time: 1hr in lab

Before leaving the field, core samples should be taken from the sandy beach from at least two tidal heights (one near the water, the second higher in the intertidal). The coring device is a simple cylinder (a simple pvc pipe or clear plastic tube will do).  If something (a cork, a finger) is used to plug the top end after the core is inserted into the sand, the sand will stay inside as the core is removed. The sand can then be shaken from the core into a container, for transport back to the lab.

Back at the lab, instructions should be given on how to prepare the sample for viewing under the dissecting scope. Also, a list and description of interstitial organisms should be provided.  Please click here for the Meiofauna Handout, which explains procedures for removing meiofauna from sand and descriptions of some common organisms.