Annual primary production of kelp Laminaria saccharina was calculated from standing crop, density, tissue carbon content and growth rate measurements at 3 sites in Rhode Island, USA -2 within Narragansett Bay and 1 in Rhode Island Sound. Results indicate similar seasonal growth patterns at all sites within Rhode Island. This pattern paralleled those in more northerly locations with rapid growth in late winter/early spring and minimal growth in summer. There was no reduction in production at the Rhode Island sites, although they are near the southern limit of this species. L. digitata was found at the most exposed sites where it compnsed up to 23 % of the total kelp density. The relative contribution of kelp to the total primary productivity varies according to season. The epiphytic community was most abundant in August and September This study is the first report of 7 species of animals epiphytic on Laminaria spp. Lacuna vincta (Mollusca) was found to be an important grazer on the Laminaria blades especially in winter.

Seasonality and distribution of macroalgae in eight Rhode Island tidepools were studied over a three-year period at 39 dates. Of the 35 taxa observed in the pools, 19 were found year-round, 11 of which were 'true' perennials. The highest number of total species (32) was found in June when spring and winter annuals overlapped, and the lowest number (20) appeared in October. Most species of green algae were found yearround (7 of 9), whereas most species of brown algae were annuals (7 of 12). The number of species of brown and red algae varied seasonally with the highest number of brown algae (12) in April and the highest number of red algae (13) in June and July. Changes in percentage cover in most tidepool macroalgae were associated with changes in water temperature and incident radiation. In seven pools, the dominant species (those which cumulatively occupied more than 50% cover) were Chondrus crispus and/or Hildenbrandia rubra. The dominant species in the highest pools were always green or brown algae. The greatest number of common species (each with more than 1 % average cover) appeared in the most wave-exposed pools. The two pools with the highest littorine (Littorina littorea L.) densities (> 500m" 2 ) supported the smallest number of common macroalgal species. Within each pool there appeared a marked seasonality of macroalgal communities. Seasonal changes in common species occurrence and abundance were similar to those previously reported for pools in northern New England, as was a conspicuous absence of a significant autumn flora, but macroalgal communities in this study demonstrated a greater seasonality. Rhode Island pools are thus both representative of other New England tidepools and unique in their own right.° uc on wick, Canada, differed between seasons and empha-Worldwide, macroalgal seasonality has been docu-sized the need for year-round observations in tidepool mented in the intertidal (Hehre and Mathieson 1970, studies. Macroalgal seasonality has been documented