Ecology

Question 1

How does the river have an influence on the neighboring water?

Answer 1

Proximity to a river run off on Svalbard usually implies sedimentation and increased turbidity of the water column

Question 2

What is the CTD measuring?

Answer 2

Salinity, temperature, density, depth and chlorophyll a (chla) fluorescence to estimate Chlorohyll a concentration, [Chl a], can be retrieved from the CTD with Chl a fluorometer measurements. As itself, the CTD measures temperature, using a resistance temperature detector, conductivity, using electrodes, and pressure, using a pressure gauge2

Question 3

What is the EcoTriplet measuring?

Answer 3

Chlorophyll a concentration, total suspended matter (TSM) and colored dissolved organic matter (CDOM) can be retrieve from the EcoTriplet measurement.

Question 4

How does the EcoTriplet measure things?

Answer 4

The EcoTriplet includes a fluorometer (for Chla and cDOM) and a backscattering sensor (TSM) and used three different wavebands to measure different substances3. Light is sent out and the substance response is captured, either as fluorescence (Chla and cDOM) or scattered light (TSM). We used blue excitation light to detect chla fluorescence (= emission) at 695 nm, UV excitation light to detect CDOM fluorescence at 460 nm and red light at 700 nm to detect TSM light scatter at 700 nm.

Question 5

What is the difference between the FRRf and the PAM?

Answer 5

In contrast to Pulse-Amplitude-Modulation (PAM) methods, FRRf only gives a single flash which induces a single photochemical event4

Question 6

What is the use of the P vs E curve?

Answer 6

assess photoacclimation of phytoplankton and to calculate photosynthetic parameters. The first part of the PE curve is represented by a linear function but with higher light intensities the curve approaches a Poisson function5. From the curve, parameters such as the photosystem II (PSII) effective absorption cross section, the saturation parameter and the maximum rate of photosynthesis can be calculated. These parameters can help to identify environmental stressors and can even indicate pigment groups or taxa present. Parameters such as the photosynthetic efficiency can also indicate the status of photoacclimation of phytoplankton by giving information about photoinhibition and (non-) photochemical quenching.

Question 7

Why are we interested in water density?

Answer 7

Density is an indicator of water mixing. Water masses from different density tends to stay distinct, floating on one another like oil on water, creating stratification.

Question 8

Why are we interested in TSM and cDOM?

Answer 8

Total suspended matter (TSM) is an indicator of water turbidity. TSM and CDOM influence light penetration in the water column.

Question 9

What is cDOM?

Answer 9

CDOM is the optically reactive fraction of the dissolve organic matter

Question 10

What can indicate an increase of TSM at the bottom of a profile?

Answer 10

The increase of TSM at the bottom of the profile can be explain by the shallowness of the station and the fact that our instrument hit the bottom, causing sediment resuspension.

Question 11

Are we able to measure cDOM?

Answer 11

No, our sensor was not sensible enough to measures the low concentration of CDOM encountered in our studied area, hence why some of the values are in the negative range.
And Geir is very mad at the company (well… as mad as Geir can be…).

Question 12

What is the light attenuation coefficient?

Answer 12

Light attenuation coefficient is a function of absorbed and scattered light due to particles and dissolved matter (Kd), which indicates how strong the light attenuation is between two depths.

Question 13

What is the photosynthetic activity?

Answer 13

Photosynthetic activity rETR (relative electron transport rate) is a function of the quantum yield of PSII fluorescence times irradiance giving us information about the photosynthetic performance of phytoplankton present at different irradiances. These plots, called PE curves, are widely used in photosynthetic research.

Question 14

What does high Ek and low α values means?

Answer 14

indicating photoacclimation of phytoplankton to high light

Question 15

What does low Ek and hight α values means?

Answer 15

This indicates adaptation of the phytoplankton at this station to low light conditions, since photosynthesis can be performed at high efficiency already at low EPAR, but saturation is reached quickly.

Question 16

What is the functional absorption cross-section?

Answer 16

The functional absorption cross-section σPSII defines the functional area of light harvesting antenna energetically coupled to PSII10 and is negatively correlated to cell size .

Question 17

What influence σPSII?

Answer 17

σPSII is influenced by many factors such as nutrients, taxonomy of the phytoplankton and changes in environmental parameters, it is difficult to interpret what contributes to the changes in σPSII during the three days

Question 18

What is the photochemical efficiency of PSII?

Answer 18

the photochemical effective efficiency (noted here as F’q/F’m), it gives us the information of fraction of open reaction centers of PSII, which can also dependent on taxa present as well as photoinhibition of fluorescence due to (non-) photochemical quenching.

Question 19

What is the maximum photochemical efficiency?

Answer 19

around 0.6

Question 20

What is the spring bloom and what controls it?

Answer 20

In polar regions marine productivity relies heavily on the spring bloom, the massive proliferation of algae, when light is available again in spring coupled with high levels of nutrients brought in from the deep over the winter. The timing of the spring bloom depends on ice build-up over the winter, temperature, winds, available sun light and many other factors. Regarding the geographical extension, it generally follows the receding ice edge northwards

Question 21

How does the typical spring bloom develop (typical succession)?

Answer 21

As Arctic spring blooms typically follow the ice edge northwards, the first phase is usually composed of ribbon-like pennate diatoms, which belong to the ecological group of sea ice algae. In a second phase, centric diatoms become the most dominant group. Typically, this second phase is first dominated by a short bloom of Thalassiosira, followed by chain-forming species of Chaetoceros, until a peak in abundance of Chaetoceros socialis concludes the bloom. The haptophyte Phaeocystis pouchetii usually blooms over a similar temporal range as Chaetoceros species.

Question 22

Why is there no pronouce zonation between species of macroalgae in Svalbard?

Answer 22

. Further south at the coast of mainland Norway, we typically find green algae intertidal, then brown algae further subtidal and finally red algae even deeper. Around Svalbard, stress from sedimentation and ice scouring reduces favourable space, and the algae is forced to grow together and intertwined

Question 23

What are the red algae (rhodophyta) that we found?

Answer 23

Dumontia contorta.

Palmaria palmata

Question 24

What are the green algae (Chlorophyta) that we found?

Answer 24

Chaetomorpha spp.
Cladophora spp.
Monostroma greullei / Ulvaria sp.

Question 25

What are the brown algae (Phaeophyceae) that we found?

Answer 25

Alaria esculenta
Desmarestia intermedia
Fucus distichus
Laminara digitata
Saccharina latissima

Question 26

Describe the life cycle of Dumontia contorta (VERY basically)

Answer 26

Late in summer the algae become fertile and disappear, leaving only the holdfast which overwinter and start producing new tissue in the spring.

Question 27

Is Palmaria palmata perennial?

Answer 27

Yes.

Question 28

Describe the two morphotypes of fucus distichus?

Answer 28

Two morphologies identified: One variety with distinctly swollen receptacles growing in the sublittoral zone on the beach (lower picture) and one smaller variety without swollen receptacles found littoral at the rock pier (upper picture). The difference in wave exposure and depth have possibly caused these differences.

Question 29

Describe station 1 (from an ecological point of vue).

Answer 29

Station 1 shows signs of a typical open water station with cold, clear water. The water is well mixed and there is an influx of warm, clear Atlantic waters on May 8. Station 1 also shows signs of the second phase of spring bloom of phytoplankton. Phytoplankton is acclimated to high light at this location.

Question 30

Describe station 2 (from an ecological point of vue).

Answer 30

Station 2 is highly influenced by the tides and the water is relatively turbid. Ecological parameters are influenced by freshwater runoff, transporting warmer, less saline and more turbig water. Station 2 shows signs of the end of spring bloom.

Question 31

Describe station 3 (from an ecological point of vue).

Answer 31

Station 3 is similar to station 2, but the influence of freshwater runoff is more pronounced at station 3. Therefore, the light attenuation is also more pronounced at station 3. Station 3 is shallow and post bloom phytoplankton is homogeneously distributed throughout the water column. Phytoplankton at both station 2 and 3 are adapted to low light conditions.

Question 32

Describe station 4 (from an ecological point of vue).

Answer 32

Station 4 is similar to station 2 and 3 with well-mixed, turbid water.

Question 33

Describe station 5 (from an ecological point of vue).

Answer 33

Station 5 can be characterized as an ice edge station with a sea ice community present. Samples suggest a transition from a typical sea ice community to the first phase of spring bloom. The water column is well mixed and small, high light adapted cells are present. It has similar ecological parameters than station 1, indicating open water conditions.

Question 34

Describe station 6 (from an ecological point of vue).

Answer 34

Station 6 is also a typical open water station with low TSM and CDOM and low light attenuation. The phytoplankton mainly seems to be high light adapted spring bloom species. The spring bloom is already in its second phase.