Ocean　Negative　Carbon　Emission　(ONCE)　involves　utilizing　natural　marine　chemistry　and　biology,　along　with　mariculture,　to　achieve　carbon　sink　goals.　Growing　awareness　of　the　interplay　between　aquaculture　and　the　coastal　carbonate　system　has　drawn　researchers’　attention　amid　ring　CO2　concentrations　and　the　negative　impacts　of　aquaculture　on　the　environment.　In　this　study,　twelve　sites　representing　different　maricultural　types　were　selected,　including　macroalgae,　shellfish,　fish,　and　non-farming　areas.　The　environmental　factors,　dissolved　inorganic　carbon　(DIC),　total　alkalinity　(TA),　and　pCO2,　were　measured　monthly　during　kelp　farming　periods.　Nitrate　is　a　major　component　of　total　nitrogen,　and　the　NO3-N　concentration　in　the　macroalgal　culture　zone　was　lower　than　others,　indicating　effective　nitrogen　removal　by　macroalgae　aquaculture.　TA　and　DIC　in　non-farmed　areas　demonstrated　larger　variation　ranges　than　in　farming　areas,　probably　due　to　the　effects　of　precipitation　on　salinity.　Aquaculture　activities　effectively　maintained　TA　and　DIC,　with　macroalgae　cultivation　playing　an　important　role　in　TA　stability,　potentially　resisting　acidification.　The　pCO2sea-air　of　macroalgae　culture　areas　in　spring　was　slightly　negative,　suggesting　carbon　sink　potential.　However,　further　research　is　needed　to　assess　the　full　extent　of　this　“fourth　type”　of　blue　carbon,　including　accurate　carbon　footprint　calculation　and　the　contributions　of　particulate　organic　carbon　and　recalcitrant　dissolved　organic　carbon.　This　study　provided　insight　into　the　comprehensive　contribution　of　different　aquaculture　types　to　the　fishery　environment　and　carbonate　system,　which　can　help　guide　aquaculture　management　and　facilitate　the　carbon-neutral　transition　of　aquaculture.　Copyright　©　2024　Zhang,　Wang,　Lei,　Zheng,　Shen　and　Mu.