METHODS

Samples of Ascophyllum nodosum were collected from the rocky inter-tidal zone at the Northeastern University marine research station in Nahant, Massachusetts. The samples sites were selected using a horizontal transect at low (waters edge at low tide), mid, high, and highest heights of the inter-tidal. The highest transect was at the upper most limit of the range of A. nodosum. The horizontal transects were approximately 14m apart, and quadrats were placed along the transect every one or two meters, depending on the presence or absence of Ascophyllum. Two samples were collected at random from the each quadrat area (0.25 m²), and the stipes were detached from hold fast. The percent coverage of A. nodosum was estimated by observation, and the presence of other flora and fauna was recorded. The samples were placed into zip-lock bags and brought to the lab for further measurements and observations.

In the lab, I observed each pair of samples from every quadrat and recorded the presence or absence of an apical tip on the main stipe, the length of the main stipe, the number of pnuematocysts. I also recorded the distance between the pnuematocysts, the number of lateral branches, and the total number of pnuematocysts on all lateral branches. In addition I recorded the number of Polysiphonia lanosa individuals present on the main stipe, the distance of each P. lanosa from the hold fast, the length and the width of the P. lanosa, and the presence of other epiphytes and epifauna. Individual P. lanosa clumps were determined by the attachment site of P. lanosa to the stipe of Ascophyllum.

To observe micro epifauna present on these samples, I immersed each pair of Ascophyllum stipes from every quadrat in cold filtered sea water. I stirred vigorously to release all organisms from the Ascophyllum and P. lanosa. The sea water was then poured into a clean Petri dish and observed under a dissecting scope. All excess water from the P. lanosa of each sample was squeezed into the corresponding Petri dish. I recorded the number and types of organisms present in each sample. I also examine the main stipe and lateral branches of each sample, collecting any broken pnuematocysts for further examination. I tried to identify all the organisms I observed and preserved a few examples in cold, filtered sea water to photograph later.

Once the stipes had been rinsed of epifauna, the clumps of P. lanosa were then removed from the A. nodosum by pinching and pulling off. I collected the epiphytes in aluminum drying dishes and recorded the wet weight. The epiphytes were dried at 70 degrees Celsius in a drying oven. The samples were weighted to the nearest .01g after three days.