Cordgrass is pushed into the current by rising tides and new growth, and quickly begins to decompose. This is what makes-up the straw-like stuff you see on our beaches, which in the fall months is added to our wrack lines.
Although you may not be familiar with this term, I’m sure you’ve searched through and near it looking for whatever “beach treasures” enticed you. Wrack lines are linear piles of marine debris (both natural and manmade) that get washed up on the beach from incoming waves and tides. Typical debris includes uprooted seagrasses, algae, seeds, mangrove leaves and propagules, along with sponges, soft corals, shells, egg cases, and worm tubes.
Unfortunately, the wrack line is also often a reminder that human-based marine debris has become a common site in the marine environment; plastics, fishing gear, cigarette butts, and drift wood are common finds. Regardless, the wrack line is an important part of the beach ecosystem. The size and duration of the wrack line can vary depending on storm activity, winds, and tide conditions. Once established, the wrack line provides shelter for a variety of animals such as insects, crabs, and amphipods thus making it a vital component of the coastal ecosystem.