Seaweeds of Long Island Sound

There is a truly amazing variery of seaweed, known to scientists as macroalgae, in the waters of Long Island Sound. Unfortunately, many shoreline visitors know seaweed only as "slimy stuff" and never experience the natural symmetry and innate beauty of the large algae. Nor do rhey appreciate the ecological and economic importance of these organisms. Until now, there have nor been many publications available to help the public appreciate and learn about the seaweeds. This guide is intended for the curious beachcomber, rather than rhe biologist, and hopefully will improve the reputation of seaweed in our region.

The Sound has such a rich variety of algae because its variety of habitats, large temperature range, shallow depth, and relatively sheltered geographic location make it an ideal environment for growth. Like the garden plants more familiar to many people, not all of them bloom at the same time. There are some, however, that thrive year-round or nearly so, such as kelp, rockweed, bladder wrack, and Irish moss. Others may appear for days, weeks, or months. About 250 species have been documented in Long Island SOlLl1dby diligent collectors over the years. Some are found in hardto-access places-for example, inside a blade of eelgrass. or within a mollusk shell. The species included here are generally common ones that you may readily encounter, plus a few that have unusual or noteworthy fearures.

Biologists put the large seaweeds into three groups according to their dominanr pigments-Chlorophyta, Phaeophyra, and Rhodophyta-or simply, green, brown, and red. All contain chlorophyll, and carry out photosynthesis, but the green color is masked in orher species by the additional brown or red pigments. These pigments absorb various frequencies of light. The limited light available at various depths in coastal waters determines the depth, or zone, in which the algae can be found. In general. greens are closest to shore, and thus highest in elevation, browns are in the intertidal (=littoral) zone and subtidal zone, and reds both farthest down and farthest from shore. There is of course some overlap.

Most seaweeds attach to rocks or other hard surfaces by means of a structure called a holdfasr, but some float freely or form mats. Seaweeds provide habitat, food, and shelter for a number of aquatic animals. In the process of photosynthesis, they produce oxygen as a byproduct, and thus help to aerate the waters.

The algae are Structurally much more simple than land plants; they do not have true roots, stems, or leaves. They are thouglu to represent the evolutionary ancestors of all the terrestrial plants, however. Despite this simplicity, many seaweeds, particularly the reds, have complex and fascinating life histories and reproductive structures. This guide will not go inro detail on that topic, but the bibiography at the end will assist those who would like ro delve further into rhe subject.