Gillian Clarke uses personification with the environment to describe the effect the war has had on it. The "ocean's lap" is described as having a "mortal stain" personifying the sea into having a black oil stain on its lap similar to that of someone spilling food while eating. This stain represents oils appearance of a blemish on the normally pristine appearance of the water. The poet also suggests the destructive nature of the oil, by using the word "mortal" to describe it, which causes the stain to be seen as the killer of the ocean.
In the fourth stanza irony has been used by Gillian Clarke when describing the "farmer's sons" and their reasons for joining the war, which is that they are "in it for the music". This is ironic as the only music of war is that of gunfire. Music is meant to be pleasing and this suggests the farmers sons turn the sound of gunfire into pleasure implying that the farmers sons joined the war for the purpose of being able to use guns. This shows that the farmers sons entered the war with a naive nature, joining the war only for the purpose of using guns. However when the reality of war sunk in, of the affect of the weapons on the environment and people, the ignorant farmers sons were changed, having to mature to adapt to the brutality of the war.
Contrast has been used at different points in the poem to emphasise how the war and through that the oil, have tarnished the environment. In the second stanza the author provides the description of a "cormorant in his funeral silk" which gives the contrast of a usually white feathered bird that is covered in the