Tidal Erotics, the collaborative exhibition by sculptor Vivienne Roche and composer John Buckley at the Hugh Lane Municipal Gallery, is intriguingly titled. It is a subtle show, and it takes a while for its layers of meaning to become apparent, but as you make your way through the four rooms it occupies, you slowly realise that while the title may be a tease, it is also aptly descriptive. To Buckley's music, you encounter intricate, delicate drawings, and sensual bronzes of seaweed that seem to float against the walls. Both drawings and sculptures vary greatly in scale, from small bunched forms to very large expansive ones. The seaweeds, fragmented and out of their natural context, are abstracted and become in effect ambiguous, analogical forms, notably suggestive of aspects of human anatomy: bones, limbs, hands, hearts and other organs. The exhibition is organised in a very deliberate, sequential way, one that is augmented by the musical pieces, which are specific to each room, and which complement the spatial lay-out with a temporal structure.

The show's origins lie in Roche's habit of walking along the beach near her home at Garrettstown in Co Cork. Many people feel an incredibly close bond to the sea, and she began to think about this bond, and the way the sea seems to link directly to our emotions. "So this work is about emotions, simple things, like love," she says with a smile. She had the idea of expressing this relationship with the sea in depictions of pieces of seaweed washed up on the beach, specifically because of the way these strange, often unlikely shapes triggered associations with human anatomy. Shaped by the water, at home in its tidal currents, they are also full of movement. So much so that movement is implicit even in the stilled plants. As it happens, movement has been a feature of Roche's prior work. In fact her first use of sculpted seaweed was as a fully functioning clapper in one of her sculpted bells, a work which combines form, sexual metaphor, movement and sound, all of which are pressed into play again here. She made many drawings of various seaweeds, laying the plants on the same sheets of tracing paper she worked on, so that often, above the drawing, you can make out the ripples produced in the paper by the damp seaweed.

Somewhere along the way, music and time became factors, because the sea is never quiet, and it functions to a strict tidal timetable. Rather than merely incorporating the sound of the sea, Tidal Erotics became a collaboration with composer John Buckley. As Roche puts it: "I see it as a set of visual and aural forms meeting in time and space." Besides the four sections, one to a room, there is also an introductory space - a prelude. This quasi-symphonic scheme (which might also suggest the seasons), is borne out by the music that forms part of each section.

When she was making the original drawings, she found that, once away from the water, the seaweeds quickly dried out and became distorted and brittle. To slow down this process while she worked on them, she applied wax, then found that she liked the effect. The bronzes in the exhibition were developed from these wax elaborations, built up on real seaweed. "The seaweeds became the armatures on which the sculptures were built. But they were sacrificed in the process, because they're physically embedded in wax, and they are destroyed with it when you make the mould. It's like a double lost-wax process," as she puts it.

The title derives from a suite of drawings in the second room of the show. Drawn directly from seaweed, the series of paired forms unmistakably resemble male and female genitalia. "The resemblance was so striking that I couldn't ignore it," she explains. The interpretation has to do with more than shape, though. It also relates to the pungent sensuality of the seashore and, for that matter, the constant, physical interplay between sea and land.

"As I see it, in the first room you have male and female forms gesturing to each other. John's music reflects this in featuring a series of dialogues between two different instruments or groups of instruments." This room is titled Soundings. Around the walls, fragmentary forms, clenched and bunched and extended, are paired off, "swimming towards each other," or actually meeting, enfolding each other. Some resemble bone joints in the way they slot neatly together. "Making connections between forms became an image of sexuality. I think of them as bodies, and when they are fused, it's a fusion of bodies."

If room two, which shares the show's overall title, is coitus, room three, titled The amen of calm waters, ("from a Derek Walcott poem"), is post-coital. It is dominated by one very large, flat bronze on the wall. At first glance it almost resembles a swan in flight. In fact it is an enormous branch of seaweed, a stem which supports a perfect, undulating fan of fronds. The final room, Ever Drifting continues the easy pace.

Several pieces are based, not on seaweed but on the ripples sculpted in sand by retreating water, patterns that are echoed in some of the seaweeds, and that evoke musical rhythms. "You have the seaweed itself, you have the patterns in the sand, and you have the water which really shapes them both. In the end it's water, flowing water, that forms everything and mediates between everything." And, strangely enough, though the one thing absent from Tidal Erotics is water, you do feel its presence in every single aspect of the show.

Tidal Erotics, by Vivienne Roche and John Buckley can be seen at the Hugh Lane Municipal Gallery until June 6th.