Neyland - Lower Salinity Area
Neyland is at the eastern end of the Haven near the Cleddau Bridge. The confluence of several rivers produces an average salinity of around 30 ppm (seawater is about 35-36 ppm at Dale) or 3 grammes per litre of water. Diatoms are affected by salinity and the variety in this area would be expected to vary to the western end of the Haven.
The common diatom species like Odontella sinesis and Bacillaria paxillifer are found up around Neyland, too, but the most dominant diatom in spring is Melosira, something we don't see in Dale. Rhabdonema also does well here along with Pleurosigma. Others which can be common are Surirella and Navicula. Both are common on the mud surface and probably become disturbed by the strong currents especially near where I take the samples (the car park on the front at Neyland). There are times when it is difficult to pull the net because of the swirling current only a few metres above the sediment.
Navicula
Surirella possibly S. fastuosa
Melosira - small chain 100 microns
Rhabdonema diatom group
Tintinnids can be extremely abundant, dominating the zooplankton. Samples in spring can be like fine sand in the samples. The lorica (shell) that they secrete and cover with minerals look a different shape to those in Dale. Lorica appearance is still the main criteria for identifying tintinnids although I still struggle to find a definitive source for reliable ID.
Another ciliate regularly appearing here is Euplotes, also common on the Gann.
Tintinnid from Neyland approx. 60 microns
In spring larval zooplankton is a mix of nauplii of the estuarine barnacle Elminius and the polychaete larvae of Polydora. This species is common an many times of the year as it passes through a number of chaetiger larval stages. Adults typically live in tubes within sediment.
A stage 3 chaetiger larva of Polydora
The ciliate Euplotes, approx 50 microns
The material above is based on early spring. Samples will be taken bimonthly over the course of a year.
Additional Material
Neyland is a new entry for 2024 and will be developed over this time.