Sandy Beaches of the Motus

The sandy beach crew sampled beaches at two different motus yesterday and found some interesting results.  Because sandy beaches tend to be low in diversity on their beach face, we changed our protocol for the Cooks to take more cores in the sand submerged in water than is our norm.  As a consequence, we found multiple species of tube worms, horn snails and crabs. One of the larger motus, Motukititu, was naturally built on uplifted coral and had the highest biodiversity of the motus we have sampled.  Honeymoon Island (also a motu) had the lowest diversity, although more studies need be conducted to make a clear connection between the structure/geomorphology of an island or given beach and its associated biodiversity.
Another interesting observation we have made about these moths revolves around the imprints in the sand.  In California, we are so used to seeing every beach filled with divots made with footsteps, we have assumed this look to be normal.  On the nearly untouched motus of Aitutaki, the beaches lack such ubiquitous divots, but do have hundreds of hermit crab tracks, shells, and pristine, smooth sand.


Day 4: Aitutaki Lagoon & Motu Intro

Today we rented a second boat.  This allowed us to take the entire class as a whole to several sites across the southern extent of Aitutaki Lagoon (across much of the lower third of the map below).  We were able to snorkel an explore a wide array of subtidal communities and get a good sense of the conditions, seascapes, and littoral landscapes that comprise this section of the lagoon.  In addition to exploring everything from just-forming Motus to rat eradication experiments, we ended our day with our first quantitative data collection at Akaimai Motu.  The icing on the cake was our beach clean-up wherein we harvested all the macroscopic trash on the motu’s seaward perimeter (we categorized and weighed all that flotsam and jetsam…more on that later).


We are again running into internet bandwidth issues, but here are some initial videos I was able to upload before burning out my internet allotment for the time being.  Check back later for additional pics and vids.