Phytoplankton community distribution in relation to environmental parameters in three aquaculture systems in a Chinese subtropical eutrophic bay

Abstract

There is concern about the impact of expanding coastal aquaculture activity, particularly in China, with the biggest aquaculture industry in the world. We conducted 3 cruises to the oyster, kelp and fish farms of the Xiangshan Bay during the winter−spring transition (02/2009), winter (01/2010) and spring (04/2010). Our aim was to explore the spatial heterogeneity of the phytoplankton community in different culture habitats and evaluate the effects of mariculture on phytoplankton. Different culture types formed unique small-scale habitats that exhibited various en vironmental gradients and forms of phytoplankton community patchiness. Both environmental (i.e. temperature, salinity, transparency, suspended solids, dissolved oxygen, pH, dissolved inorganic nitrogen, PO 4 -P, SiO 3 -Si, N/P, and total organic carbon) and phytoplankton (i.e. cell density, chlorophyll a, species richness, main dominant species, and community structure) parameters were significantly different among the 3 culture habitats. Canonical correspondence analysis showed that phytoplankton distribution was mainly influenced by temperature, nutrition, salinity and suspended solids. Oyster and kelp farming effectively alleviated coastal eutrophication and also increased species richness and diversity; fish farming did not. Temperature elevation caused by the thermal discharge from a power plant induced phytoplankton blooms during the winter and winter−spring transition. Nevertheless, the filtering effect of suspended oysters dramatically reduced microalgal biomass. The kelp and oyster farms were much better than the fish farm in terms of water quality, phytoplankton composition, and habitat restoration function. These results provide guidelines for future policy-making in aquaculture as well as eutrophication control and management.

Marine cage culture and the environment: effects on water quality and primary production

“…Additionally, the phytoplankton community composition response differed with large diatoms in the dry season being replaced by smaller species in the wet season. Another study in China reported significant differences in phytoplankton around fish farms compared to shellfish and kelp farms (Jiang et al 2012). Phytoplankton communities varied greatly in terms of abundance and species composition around the 3 types of farms and compared to samples from outside the farms, but interestingly the authors found no clear relationship between farm nutrient discharge and phytoplankton biomass.…”

“…Nash et al (2005) suggested that dissolved nutrient release may affect attached macroalgae, but that if eutrophication due to aquaculture does occur, it would be at locations distant from a farm (far-field) rather than at a local scale due to dispersal of dissolved nutrients by currents. A study in China comparing nutrient levels inside and 1000 m away from fish farms found that dissolved nitrogen doubled at the farms during warmer seasons, potentially contributing to eutrophication in the area (Jiang et al 2012). Pittenger et al (2007) concluded that discharges from farms, including nitrogen, represented a significant influx of nutrients to the marine environment.…”

“…The cessation of aquaculture activities in the semi-enclosed Tapong Bay, Taiwan, resulted in significantly decreased dissolved phosphorus levels and improved overall environmental quality (Hung et al 2008). Dissolved phosphorus levels in a study in China comparing nutrient levels inside and 1000 m away from fish farms found that dissolved phosphorus increased at the farms during warmer seasons, possibly contributing to eutrophication in the bay where the farms were sited (Jiang et al 2012). Nordvarg & Johansson (2002) measured phosphorus at farm sites in the Åland archipelago in the Baltic Sea.…”

Notitie: potentiële effecten van duurzame zeewierproductie op de biodiversiteit in de Noordzee : ecosysteem diensten en/of ecologische effecten

“…Plankton is een diverse groep van drijvende kleine en microscopische organismen in water die niet tegen de stroom in kunnen zwemmen. Het zeewier neemt nutriënten op en heeft zo een positief effect op de waterkwaliteit, het doorzicht in de waterkolom en de plankton diversiteit (Jiang et al, 2012).…”

Examining the Effects of Fish Cage Culture on Phytoplankton and Zooplankton Communities in the Southern Coast of the Caspian Sea (Mazandaran Waters– Kelarabad)

“…Farming fish in the sea has internationally spread and although it provides plenty of marine products for human consumption, alternatively puts pressure on food supplies and ocean fisheries [5]. It should be noted that the development and excessive exploitation of aquaculture in the sea has potentially had negative environmental effects, too especially farming fish enters into the water plenty of nutrients and dietary energy sources of the fish where the local effects of fish aquaculture on the environment compared to other systems, such as seaweed or shells aquaculture is at the highest level, However, its economic interests may also be at the highest level [6]. Dense fish cages provide noticeable amounts of organic waste and inorganic solution particles [7].…”