Editing Hudson Bay (section)

===Waters===
[[File:HudsonBay.MODIS.2005may21.jpg|thumb|In late spring (May), large chunks of ice float near the eastern shore of the bay, while the centre of the bay remains frozen to the west. Between 1971 and 2007, the length of the ice-free season increased by about seven days in the southwestern part of the Hudson Bay, historically the last area to thaw.]]

Hudson Bay has a lower average [[salinity]] level than that of ocean water. The main causes are the low rate of evaporation (the bay is ice-covered for much of the year), the large volume of [[Surface runoff|terrestrial runoff]] entering the bay (about {{cvt|700|km3}} annually, the Hudson Bay watershed covering much of Canada, many rivers and streams discharging into the bay), and the limited connection with the Atlantic Ocean and its higher salinity.<ref>{{Cite journal |last1=Myers |first1=Ransom A. |last2=Akenhead |first2=Scott A. |last3=Drinkwater |first3=Ken |date=1 June 1990 |title=The influence of Hudson Bay runoff and ice-melt on the salinity of the inner Newfoundland Shelf |journal=Atmosphere-Ocean |volume=28 |issue=2 |pages=241–256 |doi=10.1080/07055900.1990.9649377 |issn=0705-5900|doi-access=free |bibcode=1990AtO....28..241M }}</ref> [[Sea ice]] is about three times the annual river flow into the bay, and its annual freezing and thawing significantly alters the salinity of the surface layer. Although its exact effects are not fully understood currently, the [[Cyclone|cyclonic]] storms in the bay are responsible for synoptic variability of salinity along the coast.<ref>{{Cite journal |last1=Dmitrenko |first1=Igor A. |last2=Kirillov |first2=Sergei A. |last3=Babb |first3=David G. |last4=Kuzyk |first4=Zou Zou A. |last5=Basu |first5=Atreya |last6=Ehn |first6=Jens K. |last7=Sydor |first7=Kevin |last8=Barber |first8=David G. |date=15 September 2021 |title=Storm-driven hydrography of western Hudson Bay |url=https://www.sciencedirect.com/science/article/pii/S0278434321001813 |journal=Continental Shelf Research|volume=227 |pages=104525 |doi=10.1016/j.csr.2021.104525 |bibcode=2021CSR...22704525D |issn=0278-4343}}</ref>

One consequence of the lower salinity of the bay is that the [[Melting point|freezing point]] of the water is higher than in the rest of the world's oceans, thus decreasing the time that the bay remains ice-free. The increase of river inflows during the winter has decreased the season of sea ice by more than one month since the 1960s.<ref>{{Cite journal |last1=Eastwood |first1=Rosemary Ann |last2=Macdonald |first2=R. W. |last3=Ehn |first3=J. K. |last4=Heath |first4=J. |last5=Arragutainaq |first5=L. |last6=Myers |first6=P. G. |last7=Barber |first7=D. G. |last8=Kuzyk |first8=Z. A. |date=1 June 2020 |title=Role of River Runoff and Sea Ice Brine Rejection in Controlling Stratification Throughout Winter in Southeast Hudson Bay |journal=Estuaries and Coasts|volume=43 |issue=4 |pages=756–786 |doi=10.1007/s12237-020-00698-0 |s2cid=212641648 |issn=1559-2731|doi-access=free |bibcode=2020EstCo..43..756E |hdl=1993/34772 |hdl-access=free }}</ref>

The lower salinity of the bay also has effects on the distribution and prevalence of common marine life such as micro algae. Research has shown that the lower salinity of the Hudson Bay limits the growth of micro algae, which causes a notable change in biomass along the bay's salinity gradient.<ref>{{Cite journal |last1=Legendre |first1=Louis |last2=Martineau |first2=Marie-Josée |last3=Therriault |first3=Jean-Claude |last4=Demers |first4=Serge |date=1 September 1992 |title=Chlorophyll a biomass and growth of sea-ice micro algae along a salinity gradient (southeastern Hudson Bay, Canadian Arctic) |url=https://doi.org/10.1007/BF00243115 |journal=Polar Biology|volume=12 |issue=3 |pages=445–453 |doi=10.1007/BF00243115 |bibcode=1992PoBio..12..445L |s2cid=42347421 |issn=1432-2056}}</ref>