Biological Offshore Results

Zooplankton

Phytoplankton

A) Abundance of Phytoplankton Species at Station 61

B) Abundance of Phytoplankton Species at Station 62

C) Abundance of Phytoplankton Species at Station 64

D) Abundance of Phytoplankton Species at Station 66

E) Abundance of Phytoplankton Species at Station 67

Figures 2 A-E illustrate the abundance of phytoplankton species at each station offshore of the Fal Estuary. Data was collected on 02/07/2014 between 07:15 and 18:00 UTC.

A) Station 62

B) Station 64

C) Station 66

D) Station 67

Figures 1 A-D illustrate the abundance of zooplankton species at stations 62, 64, 66 and 67 along the transect offshore of the Fal Estuary. The data was collected on 02/07/2014 between 07:15 and 18:00 UTC.

Generally, the observed zooplankton community was completely dominated by cladocerans, copepods and hydromedusae. This may have been a sampling bias due to strict sampling of chlorophyll maximums and columns of thermally stratified water parcels. Deeper water yielded a higher species diversity but lower species abundance compared to surface samples throughout all stations, with the exception of station 64 (figure 1B). There was no significant difference in species diversity throughout the stations, with a total range of 9-11 different species observed. Abundance of the dominant species did vary between stations, but this may be attributed to the counting technique utilised.

There were no truly dominant species observed throughout any of the stations sampled, although a definite trend of diatomic dominance was apparent. Station 61 (Figure 2A) exhibited high levels of the diatoms Rhizosolenia delicatula and Thallisoriora rotula, as well as a high abundance of dinoflagellates, in surface layers. Most other groups were not apparent at the station, or were present in very low numbers as depth increased. Station 62 (Figure 2B) was populated exclusively with the diatoms Chaetoceros spp and Guinardia delicatola at all depths, with the latter species becoming more abundant at bottom layers. At station 64 (Figure 2C) the surface layers were sampled only; the previously mentioned species were abundant in similar amounts, although interestingly the bloom forming dinoflagellates Karenia mikimotoi and Gyrodinium spp were present. Station 66 (Figure 2D) was dominated mainly by Thallisoriora and the diatom Mesodinium rubrum at the two mid-column sampling sites. Bottoms waters were abundant in both diatoms and dinoflagellates, with no species observed to be particularly highly abundant. Station 67 (Figure 2E) exhibited a high abundance of Leptocylindrus spp within the surface layers, accompanied by a high species diversity of both dinoflagellates and diatoms.

Disclaimer - These views are of the students of group 11 only and do not reflect the views and opinions of the National Oceanography Centre or the University of Southampton.