Περίληψη:
Alterations in phytoplankton biomass, community structure and timing of
their growth (phenology), are directly implicated in the carbon cycle
and energy transfer to higher trophic levels of the marine food web. Due
to the lack of long-term in situ datasets, there is very little
information on phytoplankton seasonal succession in Cyprus (eastern
Mediterranean Sea). On the other hand, satellite-derived measurements of
ocean colour can only provide long-term time series of chlorophyll (an
index of phytoplankton biomass) up to the first optical depth (surface
waters). The coupling of both means of observations is essential for
understanding phytoplankton dynamics and their response to environmental
change. Here, we use 23 years of remotely sensed, regionally tuned
ocean-colour observations, along with a unique time series of in situ
phytoplankton pigment composition data, collected in coastal waters of
Cyprus during 2016. The satellite observations show an initiation of
phytoplankton growth period in November, a peak in February and
termination in April, with an overall mean duration of 4 months. An
in-depth exploration of in situ total Chl-a concentration and
phytoplankton pigments revealed that pico- and nano-plankton cells
dominated the phytoplankton community. The growth peak in February was
dominated by nanophytoplankton and potentially larger diatoms (pigments
of 19’ hexanoyloxyfucoxanthin and fucoxanthin, respectively), in the
0-20 m layer. The highest total Chl-a concentration was recorded at a
station off Akrotiri peninsula in the south, where strong coastal
upwelling has been reported. Another station in the southern part,
located next to a fish farm, showed a higher contribution of
picophytoplankton during the most oligotrophic period (summer). Our
results highlight the importance of using available in situ data coupled
to ocean-colour remote sensing, for monitoring marine ecosystems in
areas with limited in situ data availability.
Συγγραφείς:
Demetriou, Monica
Raitsos, Dionysios E.
Kournopoulou, Antonia
and Mandalakis, Manolis
Sfenthourakis, Spyros
Psarra, Stella
