Kepteki­wiku’s: To freeze or not to freeze

In the Bras d'or Lake Bio­sphere Re­serve

The Victoria Standard - - Environment - ANNAMARIE HATCHER

It will soon be Novem­ber in the Bras d’or Lake Bio­sphere and in the Mi’kmaw cal­en­dar that is ‘Rivers start­ing to freeze time’ (Kepteki­wiku’s). As I think back over past au­tumns, I won­der whether the rivers will ac­tu­ally start to freeze in Novem­ber, and how that may change with our chang­ing cli­mate. Shall we think about re-nam­ing Kepteki­wiku’s? Let’s ex­am­ine this pro­posal.

The cal­en­dar on my wall, com­puter and cell phone is called the Gre­go­rian cal­en­dar af­ter Pope Gre­gory XIII who in­tro­duced it in 1582. It is a so­lar cal­en­dar based on a 365-day year di­vided into 12 months of ir­reg­u­lar lengths with an ex­tra day added nearly ev­ery 4 years. Many great minds came up with that plan, but it took a pope to im­ple­ment it! Although we at­tempt to track Mi’kmaw months along­side Gre­go­rian cal­en­dar months, they are not re­ally equiv­a­lent. There are ac­tu­ally 13 moon cy­cles in the tra­di­tional Mi’kmaw cal­en­dar ev­ery year. Each cy­cle starts with the new moon and is named af­ter a sig­nif­i­cant en­vi­ron­men­tal oc­cur­rence at that time. A lu­nar month is equiv­a­lent to the time that the moon takes to pass through each of its phases (new moon, half moon and full moon) and re­turn back to its orig­i­nal po­si­tion - this takes ap­prox­i­mately 29.5 days. A lu­nar year there­fore has ap­prox­i­mately 354 days. The Gre­go­rian cal­en­dar is based on a so­lar year which has about 365 days. This leaves an 11-day dif­fer­ence be­tween one so­lar year and one lu­nar year and at least part of a thir­teenth month. This year, the Novem­ber moon is Nov 6 to Dec 6. Does that time pe­riod seem more likely for ‘rivers start­ing to freeze’?

Ice-up con­di­tions at two En­vi­ron­ment Canada stream gaug­ing sta­tions re­ported over the last ten to twelve years may pro­vide in­sight into freez­ing pat­terns in the Bio­sphere. Ice for­ma­tion in the Mid­dle River can start as early as De­cem­ber 4, as was mea­sured in 2007 and Novem­ber 29 in the River Denys as noted that same year. How­ever, tim­ing of ice for­ma­tion de­pends upon the hy­drol­ogy of the river (wa­ter ve­loc­i­ties and the in­flow of warmer ground wa­ter). In Glen Brook, near Melford, tem­per­a­tures mea­sured dur­ing some Novem­ber days showed a huge range, from 1.7 to 10 de­grees be­tween 2001 and 2015. So, rivers may start to freeze dur­ing Kepteki­wiku’s, but it is prob­a­bly a bit of shell ice in the shal­lows, and it is de­pen­dent on time, lo­ca­tion and ge­ol­ogy in the Bras d’or Lake Bio­sphere.

The Bras d’or Lake Bio­sphere is in the cen­tre of Unama’ki, one of the seven tra­di­tional dis­tricts of Mi’kma’ki. The orig­i­nal seven dis­tricts ex­tend from the Gaspe re­gion of Que­bec to the north­ern part of Maine. Present day con­di­tions for ‘rivers start­ing to freeze’ are clearly more prob­a­ble near the north­ern parts of Mi’kma’ki. For ex­am­ple, air tem­per­a­tures mon­i­tored by En­vi­ron­ment Canada at the South Te­tagouche sta­tion near Bathurst, New Brunswick, yielded much lower ‘cli­mate nor­mal’ tem­per­a­tures than Bad­deck dur­ing Novem­ber for the years 1981 to 2010. Although I don’t have wa­ter tem­per­a­tures from that area, those air tem­per­a­tures say to me that rivers start­ing to freeze is a very likely sce­nario dur­ing the Novem­ber moon in South Te­tagouche. Ice-up in the Pe­ta­co­diac River near Monc­ton, in the mid­dle of Mi’kma’ki sup­ports that con­clu­sion. In a tech­ni­cal re­port by D. Caissie in 2000 (Cana­dian Tech­ni­cal Re­port of Fish­eries and Aquatic Sci­ences 2301) it was shown that ice-up oc­curred be­fore Novem­ber 11 on av­er­age 77% of the time be­tween 1962 and 1996. It seems likely that the Novem­ber moon may have earned its’ name in one of the other dis­tricts of Mi’kma’ki.

With a chang­ing cli­mate and warm­ing oceans, the time gap be­tween the Novem­ber moon and Kepteki­wiku’s, or rivers start­ing to freeze time, is likely to widen. As we are sur­rounded by wa­ter, our cli­mate is strongly in­flu­enced by oceanic pro­cesses. This end of the province is in­flu­enced by the northerly flow­ing Labrador cur­rent whereas the south­ern end feels the in­flu­ence of the warm Gulf Stream. So, if we look closely at the sci­en­tific mod­el­ling re­lat­ing global cli­mate change to the Labrador cur­rent, the pic­ture is clear. We are in for a warmer ocean and warmer Novem­bers in the fu­ture with the gap be­tween the Novem­ber moon and ‘rivers start­ing to freeze’ ever-widen­ing!

Dr. Annamarie Hatcher is a con­sult­ing ecol­o­gist and a board mem­ber of the Bras d’or Lake Bio­sphere Re­serve As­so­ci­a­tion. Thanks are due to Lynn and Fred Baech­ler who are al­ways ready to share data! For more in­for­ma­tion about the Bras d’or Lake Bio­sphere Re­serve As­so­ci­a­tion, please visit http://blbra.ca/.

Ma­jor cur­rents of the North­east At­lantic. Warm cur­rents are col­ored with reds and colder cur­rents with blues. Map cour­tesy of Gulf of Maine’ Cen­sus of Ma­rine Life (COML) - www.gul­fof­maine-cen­sus.org.

Data cour­tesy of En­vi­ron­ment and Cli­mate Change Canada (canada.ca)

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