LISTSERV mailing list manager LISTSERV 15.5

Help for FISH-SCI Archives


FISH-SCI Archives

FISH-SCI Archives


View:

Next Message | Previous Message
Next in Topic | Previous in Topic
Next by Same Author | Previous by Same Author
Chronologically | Most Recent First
Proportional Font | Monospaced Font

Options:

Join or Leave FISH-SCI
Reply | Post New Message
Search Archives


Subject:

Re: Climate change and fish

From:

Shawn Booth <[log in to unmask]>

Reply-To:

Scientific forum on fish and fisheries <[log in to unmask]>

Date:

Wed, 17 Jan 2018 21:17:41 +0000

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (1 lines)


><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
           REPLIES WILL BE SENT TO THE FISH-SCI LIST
<>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><

Without going into all the complexities I always believe that absolute temperature changes are the best indicator (i.e., changes in degrees celsius) to start with, their something that eveyone understands as I would call them the most basic type of data. TK alluded to scientific reasons why, but I think in addition one of the big players is bound to be changes in salinity gradients withdue to more freshwater run-off either through glacier or permafrost melt in the Arctic. However, I could see some validity to making statements in line with a certain degree unit change may have a certain percent change (ideally a range) in specific types of habitats/populations/dissolved oxygen etc.


Best of the New Year to all ye Fishfolkers,

Shawn Booth.


________________________________
From: Scientific forum on fish and fisheries <[log in to unmask]> on behalf of [log in to unmask] <[log in to unmask]>
Sent: January 17, 2018 9:11 AM
To: [log in to unmask]
Subject: Re: Climate change and fish

><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
           REPLIES WILL BE SENT TO THE FISH-SCI LIST
<>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><

Chris,

The problem with your suggestion is that measurements of temperature
(unlike precipitation) are necessarily related to an arbitrary zero.
Thus, a "1%" change in the numerical value is meaningless.

For example, if the Atlantic Water entering the Barents Sea was to
warm from 3 to 4 Celsius, it might look like a 33% increase but it
could just as well be a 5% increase (in Fahrenheit) or even 0.4% (in
Kelvin). Even if we just used a "modified Celsius" for oceanographic
purposes, with zero at the freezing point of seawater, rather than
fresh, the change would be a "mere" 19%. With such a spread of
numerical values, none of them can convey any understanding.

You could try defining a "biological zero", at which all biological
activity would shut down, but that is likely to vary from one
ecosystem to another, which would further complicate interpreting
percentage changes.

Better to stick to a straightforward, understandable measure (e.g.
increases in Celsius units) for the simple stuff and then get busy
with understanding and explaining projections in ecological and
ecosystem terms. For the Arctic Ocean, that won't be a matter of
temperature increases so much as the degree of penetration of various
water masses and the ecosystems found within them, the dominant effect
of salinity on seawater density once temperatures are around the
freezing point, the implications of surface mixing and sunlight
penetration in the absence of ice cover, etc. etc. Temperature change
is a very crude proxy for all of that and hence one that is best kept
as simple as possible.


Trevor Kenchington



Quoting Chris Harrod <[log in to unmask]>:

>> <> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
> REPLIES WILL BE SENT TO THE FISH-SCI LIST
> <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><
>
> Folks
>
> A quick question. In many climate change projections, temperature
> changes are reported in C shift from baseline, while precipitation
> (or discharge) is provided in % terms.
>
> What are peoples' thoughts regarding presenting temperature change
> as a % - as a means of highlighting those areas where changes are
> going to be large (e.g. Arctic). I appreciate that giving a C value
> allows estimated of effects on vital rates etc.
>
> Cheers
> Chris
>
>
>> <> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
> Professor Chris Harrod
> (Fish & Aquatic Ecology)
>
> Email: [log in to unmask]<mailto:[log in to unmask]>
> Twitter: @chris_harrod
> www.harrodlab.net<http://www.harrodlab.net>
> HarrodLab: Fish and Stable Isotope Ecology Laboratory
> Instituto de Ciencias Naturales Alexander von Humboldt,
> Universidad de Antofagasta,
> Avenida Angamos 601, Antofagasta, Chile
> Chile Mobile: +56 9 7399 7792
> Chile Office: +56 55 2637400
> <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><
>
>
>> <> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
> For information, send INFO FISH-SCI to [log in to unmask]
>
> The FISH-SCI List Archive
> http://segate.sunet.se/cgi-bin/wa?A0=FISH-SCI
>
> To cancel your subscription, send a blank message to:
> [log in to unmask]
> <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><
>

><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
For information, send INFO FISH-SCI to [log in to unmask]

                   The FISH-SCI List Archive
         http://segate.sunet.se/cgi-bin/wa?A0=FISH-SCI

     To cancel your subscription, send a blank message to:
           [log in to unmask]
<>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><

><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
For information, send INFO FISH-SCI to [log in to unmask]

                   The FISH-SCI List Archive
         http://segate.sunet.se/cgi-bin/wa?A0=FISH-SCI

     To cancel your subscription, send a blank message to:
           [log in to unmask]
<>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <>< <><


Back to: Top of Message | Previous Page | Main FISH-SCI Page

Permalink



LISTSRV.NORDU.NET

CataList Email List Search Powered by the LISTSERV Email List Manager