Limits...
Increasing nitrogen limitation in the Bothnian Sea, potentially caused by inflow of phosphate-rich water from the Baltic Proper.

Rolff C, Elfwing T - Ambio (2015)

Bottom Line: This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water.The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water.The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms.

View Article: PubMed Central - PubMed

Affiliation: Stockholm University Baltic Sea Centre, 106 91, Stockholm, Sweden. carl.rolff@su.se.

ABSTRACT
The study showed that the open water of the Bothnian Sea (BS) is likely to have shifted from altering nitrogen and phosphorous limitations of the spring bloom to more nitrogen-limited conditions during the last 20 years. This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water. The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water. The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms. There does not appear to be any immediate concern in the short-term perspective for the state of the BS, but a progression of the processes may lead to a more eutrophic state of the BS.

No MeSH data available.


Related in: MedlinePlus

Salinity (PSU), oxygen concentration (ml L−1, oxygen required to oxidize H2S as negative oxygen concentration), phosphate concentration (μmol L−1), DIN (μmol L−1), and Φ (μmol N L−1) at stations BY29 (nBP) and SR5/C4 (BS). For station SR5/C4, November–December data were used, but for BY29, January–February data were used because of better data coverage and better representation of winter concentrations. Note that time and color scales differ between stations and that they have been cut to exclude extremes. The upper and lower levels of the color scales should therefore be interpreted as “or greater” and “or less” respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4591228&req=5

Fig4: Salinity (PSU), oxygen concentration (ml L−1, oxygen required to oxidize H2S as negative oxygen concentration), phosphate concentration (μmol L−1), DIN (μmol L−1), and Φ (μmol N L−1) at stations BY29 (nBP) and SR5/C4 (BS). For station SR5/C4, November–December data were used, but for BY29, January–February data were used because of better data coverage and better representation of winter concentrations. Note that time and color scales differ between stations and that they have been cut to exclude extremes. The upper and lower levels of the color scales should therefore be interpreted as “or greater” and “or less” respectively

Mentions: February values are generally considered as being the most representative for winter season’s inorganic nutrients. In this study, data obtained from the November to December cruise were used also for the nBP and ÅS with the exception of water column description as shown in Fig. 4. In the BB and BS, the winter has progressed considerably further during November–December than in the nBP. To ensure that there were no considerable differences in Φ values calculated from January to February, in relation to November–December values, a time series of monthly values from the years 1990 to 1999 were investigated. Such data were obtainable for stations BY31, US5b/C1, and station F9/A13 in the southern BB (not indicated in Fig. 1).


Increasing nitrogen limitation in the Bothnian Sea, potentially caused by inflow of phosphate-rich water from the Baltic Proper.

Rolff C, Elfwing T - Ambio (2015)

Salinity (PSU), oxygen concentration (ml L−1, oxygen required to oxidize H2S as negative oxygen concentration), phosphate concentration (μmol L−1), DIN (μmol L−1), and Φ (μmol N L−1) at stations BY29 (nBP) and SR5/C4 (BS). For station SR5/C4, November–December data were used, but for BY29, January–February data were used because of better data coverage and better representation of winter concentrations. Note that time and color scales differ between stations and that they have been cut to exclude extremes. The upper and lower levels of the color scales should therefore be interpreted as “or greater” and “or less” respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4591228&req=5

Fig4: Salinity (PSU), oxygen concentration (ml L−1, oxygen required to oxidize H2S as negative oxygen concentration), phosphate concentration (μmol L−1), DIN (μmol L−1), and Φ (μmol N L−1) at stations BY29 (nBP) and SR5/C4 (BS). For station SR5/C4, November–December data were used, but for BY29, January–February data were used because of better data coverage and better representation of winter concentrations. Note that time and color scales differ between stations and that they have been cut to exclude extremes. The upper and lower levels of the color scales should therefore be interpreted as “or greater” and “or less” respectively
Mentions: February values are generally considered as being the most representative for winter season’s inorganic nutrients. In this study, data obtained from the November to December cruise were used also for the nBP and ÅS with the exception of water column description as shown in Fig. 4. In the BB and BS, the winter has progressed considerably further during November–December than in the nBP. To ensure that there were no considerable differences in Φ values calculated from January to February, in relation to November–December values, a time series of monthly values from the years 1990 to 1999 were investigated. Such data were obtainable for stations BY31, US5b/C1, and station F9/A13 in the southern BB (not indicated in Fig. 1).

Bottom Line: This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water.The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water.The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms.

View Article: PubMed Central - PubMed

Affiliation: Stockholm University Baltic Sea Centre, 106 91, Stockholm, Sweden. carl.rolff@su.se.

ABSTRACT
The study showed that the open water of the Bothnian Sea (BS) is likely to have shifted from altering nitrogen and phosphorous limitations of the spring bloom to more nitrogen-limited conditions during the last 20 years. This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water. The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water. The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms. There does not appear to be any immediate concern in the short-term perspective for the state of the BS, but a progression of the processes may lead to a more eutrophic state of the BS.

No MeSH data available.


Related in: MedlinePlus