Impacts of ocean acidification on marine life in Long Island Sound. Christopher J. Gobler, PhD

Transcription

1 Impacts of ocean acidification on marine life in Long Island Sound Christopher J. Gobler, PhD

2

3 Ocean acidification Lower ph, acidification

4 Calcifying shellfish potentially vulnerable to ocean acidification

5 Top fisheries in New York, 2012, NMFS data The success of NY s fisheries depends on the ability of marine animals to successfully calcify.

6 Percent survival Bay scallop Hard clam CO2 (ppm)

7 Hard clam Bay scallops Low CO 2 High CO 2

8 Cross-section of juvenile clams

9 Calcifying shellfish negatively affected by ocean acidification X? X? X X

10 Ocean acidification and fish: One less thing to worry about?

11 80 70 (a) Survival (%) Inland silverside, Menidia beryllina r 2 = CO 2 concentration (ppm)

12 Forage fish: an important energetic link

13 But the commercial and recreational fish are OK?

14 Larval summer flounder are highly vulnerable to OA Chambers et al 2014 US fisheries are valued at >$5B annually.

15

16 Coastal ocean acidification: Why wait? A combination of regional and local factors can exacerbate acidification :

17 Take a deep breath Oxygen (O 2 ) Carbon dioxide (CO 2 )

18 Nitrogen loading leads to low oxygen and high CO 2 Nitrogen loading Phytoplankton CH 2 O + O 2 Consumed Respiration CO 2 + H 2 O Produced More algae and warm temperatures during summer make bacteria hyperventilate

19 Nutrient discharge into coastal zone Nutrients stimulate algal blooms Decay of algae = CO 2, ph, DO

20 The annual occurrence of hypoxia and acidification in Long Island Sound

21 Co-occurrence of low oxygen and acidification in Long Island Sound The intensity of acidification in Long Island Sound during summer exceeds levels project for the open ocean in Wallace et al, 2014, ECCS NYC

22 The seasonality of acidification and hypoxia in Long Island Sound Wallace et al, 2014, ECCS; CTDEEP data set NYC

23 Temporal dynamics of acidification, Western Long Island Sound, bottom water ph, 2014 ph > 1 month acidic /23 07/13 08/02 08/22 09/11

24 Bottom DO & ph from western LIS (st. A4) DO (mg L ¹) DO ph ph /15/10 12/15/10 4/15/11 8/15/11 12/15/11 4/15/12 8/15/12 12/15/12 7

25 How does acidification and low oxygen effect marine life? Credit: Travis Dove Photography

26 Bubbling with N 2 gas, CO 2 gas, and air to create hypoxic and/or acidified conditions CO Air 2 [O N 2 ] 2 [CO 2 ] ph

27 Experimental dissolved oxygen and ph levels achieved via mixtures of N 2, CO 2, and air Dissolved oxygen (mg L -1 ) Control Hypoxic Acidified Hypoxic & acidified ph (total scale) Days post-metamorphosis Control Hypoxic Acidified Hypoxic & acidified Days post-metamorphosis Gobler et al 2014, PLOS One

28 Growth of juvenile hard clams (4 months old) exposed to low oxygen and acidification 15 Growth rate (µm d -1 ) Control Low oxygen Low ph Low oxygen, low ph Gobler et al 2014, PLOS One

29 Survival of larval silversides exposed to low oxygen and low ph (acidification) Percent survival Low ph 0 and low DO reduced survival and their combined effects were synergistic Control Low ph Low oxygen Low oxygen, low ph Depasquale et al, 2015, MEPS

30 Are there effects in an ecosystem setting? The Forge River, NY, USA ph (total scale) ph Dissolved oxygen /30/2012 7/10/2012 7/20/2012 7/30/2012 8/9/2012 8/19/2012 Dissolved oxygen (mg L -1 )

31 Amending hypoxic and acidified water via sodium carbonate addition and aeration ph (total scale) Unamended Carbonate Aeration Days post fertilization Dissolved oxygen (mg L -1 ) Unamended Carbonate Aeration Days post-fertilization Gobler et al 2014, PLOS One

32 Effects of carbonate and aeration on survival bay scallop larvae in hypoxic and acidified water Percent survival ph effect Aeration Sodium carbonate Unammended High ph, High DO High ph, low DO Low ph, low DO Gobler et al 2014, PLOS One

33 Effects of hypoxia and acidification on size of bay scallop larvae 1000 O 2 effect 800 Larval length (µm) Aeration Sodium carbonate Unammended High ph, High DO High ph, low DO Low ph, low DO Gobler et al 2014, PLOS One

34 Excessive nitrogen loading leads to hypoxia or low oxygen Day Night Photosynthesis produces oxygen Respiration consumes oxygen No photosynthesis Respiration consumes oxygen Oxygen high Oxygen low Sediment Sediment

35 How do diurnal patterns in ph and DO affect marine life? ph (total scale) Salt marsh, Shinnecock Bay, NY ph DO DO (mg per L) /1/14 8/2/14 8/3/14 8/4/14 8/5/14 8/6/14

36 Experimental patterns in hypoxia ph DO and acidification ph T Dissolved oxygen (mg L -1 ) 7 0 Date/Time Clark and Gobler, in prep

37 Survival (%) Survival of larval scallops exposed to chronic and diel fluctuations in hypoxia and acidification 0 Ambient Low ph Diurnal ph Low DO Diurnal DO Low ph/do Clark and Gobler, in prep Treatment Diurnal ph/do

38 The fate of marine ecosystems under OA? - complex; many interactions, many unknowns X?? X? X? X

39 Conclusions: US East Coast estuaries experience hypoxia and acidification during the seasons when early life stage fish and shellfish are spawned and are developing. The levels of hypoxia and acidification attained in estuaries can both additively and synergistically depress the growth and survival of multiple early life stage forage fish and bivalves. Diurnal fluctuation in acidification and hypoxia provides a refuge for some but not all larval bivalves.

40 The End